Why don't you take a deep breath Star lol

Yeah, there was a lot of stuff that could've been done better. However, unfortunately SW always does stupid stuff, Maul was wasted, so was Dooku, Jango Fett, Boba Fett, Phasma. They have a tendency to introduce cool characters with potential and then waste them... Ep. 3 should have been 2 movies and then the last prequel should have been a better version of Rogue One -which in itself was... fine. But still. Ep. 6 ended dumb because the plot was just Ep. 4 recycled, essentially. I didn't mind TFA since it set up a lot of interesting things, and then TLJ got rid of the majority of what was set up. So Ep. 7 is almost pointless. 

I think that was the point. Her acting suspicious was meant to make the audience think she was up to something. 

Remember, they came out of light speed and arrived at this system for a reason, trailing off towards the planet would have given it all away, so they kept on their path to get close enough so the smaller vessels to sneak to the planet. She was sticking to Leia's plan.

Also, in chain of command she doesn't have to tell Poe anything, she's the one in charge, not some arrogant pilot who while taking down a massive ship, also cost the lives of numerous others because he didn't follow an order. She was one of the better parts of the film.

The opening screen crawl of "The Last Jedi" states pretty clearly otherwise:

"The FIRST ORDER reigns. Having decimated the peaceful Republic, Supreme Leader Snoke now deploys his merciless legions to seize military control of the galaxy.  Only General Leia Organa’s band of RESISTANCE fighters stand against the rising tyranny"

Coruscant is at the Galactic Core.  I'm pretty sure there is dialogue in the film that reaffirms the First Order has already established/is establishing control over the majority of the galaxy.  At the abandoned base at the end, they also make it very clear that the Rebellion's only hope for aid could only come from the Outer Rim territories.  I think we're supposed to infer that The First Order was able to wipe out The Republic relatively quickly after StarKiller Base obliterated the Republic's capital and Senate in "The Force Awakens".  From Wookiepedia:

"The Hosnian Cataclysm, also known as the destruction of Hosnian Prime, was the destruction of the Hosnian system at the hands of the First Order thirty years after the Battle of Endor. The event took place during the Cold war and marked the annihilation of Hosnian Prime, the capital of the New Republic. Its destruction was carried out by Starkiller Base, a superweapon capable of destroying entire star systems. With the destruction of Hosnian Prime came the destruction of the Galactic Senate and part of the New Republic Starfleet. The destruction of the system was visible from around the galaxy, including the planets of Takodana and Vardos.

Though stunned by the events, the armed forces fighting the First Order, commanded by General Leia Organa, immediately began their response. The Resistance successfully destroyed the Starkiller weapon, ensuring it would never eliminate another star system again. However, the extermination of the Galactic Senate and a large part of the Republic Starfleet, as well as the massive loss of life, left both the New Republic and the Resistance in a vulnerable position. "

I liked her. But I think her being a double agent just would have been more satisfying. I've heard she's pretty awesome in the EU books. But most people won't read those

No, but she could read a situation. As I stated, if she wanted to keep Poe in the dark then she should have the good sense to know this arrogant pilot is a risk in a dire situation. Lock him up and guard him.  If he breaks out with help she did what she could to prevent the mutiny.  Instead she antagonizes a well respected figure known for being reckless ensuring a mutiny.  She has been in command for minutes, she should understand that chain of command has broken down and trust is earned. Leia could say "trust me" and Poe would follow.  Who is Aldo? What is her track record?  It is perfectly reasonable to think she is either incompetent (she is) or working against them.  

Also the Finn/Rose story line was absolutely pointless!!!! It could have been removed and saved 30 minutes off the movie. She was such a one dimensional, generic character that only pissed me off more with the super awkward kiss. Just the whole casino planet and Benecio Del Toro's hacker character, everything led to NOTHING in that story arc!

Help me with the timeline then.

My understanding was Force Awakens ends with Starkiller base exploding, and Rey goes to see Luke.  Last Jedi opens with Rey at the exact moment handing the light sabre to Luke.  If I were to guess all of Last Jedi takes place within a week right after the conclusion of Force Awakens.

So, within a week the First Order blitzed the Republic and crushed the resistance to a small handful?  I can accept it, but pacing wise it is jarring to think went from peace, to war, to conquest within a month on an interstellar level. I'll say it is not in my top five issues with the Last Jedi.

I don't disagree with you.  However, the opening crawl and the dialogue still states that the Republic has been "decimated".  Is it sloppy story telling?  Sure.  But, it's par for the course in Disney's chosen narrative for their Star Wars trilogy.  Where did The First Order come from?  Unexplained.  Why is there still a Rebellion after the establishment of The New Republic.  Unexplained.  Why isn't The New Republic at war with The First Order?  Unexplained.  They leave it up to the viewer to dig up the answers outside the films.  Here is what I found (I'm guessing this comes from the books that have been published in the last few years which Disney says are canon):

"A peace treaty was signed that ended both the Empire and the Rebellion. Mon Mothma formally established the New Republic and passed the Military Disarmament Act, ensuring that the new government would have neither troops nor starships.  As her term ended, Leia also became aware that a mysterious organization, the First Order, was gaining strength in the outer reaches of the galaxy. In an attempt to counter this new threat, aware that the New Republic could not become a military force, she began gathering allies into a small and private group. They called it the Resistance.  In order to establish the first Resistance Base, the group decamped to a planet called D’Qar, a planet that had been scouted decades before by the Rebel Alliance. This is where Leia and her followers were as they watched the First Order blow up the New Republic. As “The Last Jedi” begins, there is no government in the galaxy, and the First Order is on the march."

https://www.nytimes.com/2017/12/06/watching/star-wars-resistance-rebellion.html

According to that, The Republic in The Force Awakens has no military whatsoever.  So, when the capital and Senate get blown up by The First Order in The Force Awakens, that's pretty much it for the Republic.  There's no organized military machine in place to prevent The First Order from seizing control.  And no Republic fleet to send aid anywhere.  There is just Leia and her Rebels.

I figured the First Order was a remnant of the Empire licking its wounds and rebuilding its strength after defeat.  I never did get the dynamics of the galaxy in VII so I had to look up what planets got destroyed.  I know people hated the politics of the prequels, but two three minute scenes of Leia explaining the need to organize to a Prime Minister and the threat of the First Order would have helped lay the ground work real quick.

Scene 1 - Prime Minister Office (Establish planet of New Republic to call back to when it gets blown up)

"You're no longer a General, Princess Organa, the days of war have long passed"
"Prime Minister, the Empire was driven to the Outer Rim, but they have been regrouping and we have reports they've begun taking systems. We should prepare to meet them when the time comes."
"I'll not hear paranoid delusions that could sink us into debt or conflict, we will not escalate matters, the fleet will remain decommissioned. Now, i have work to attend to, good day."

Scene 2 - Meeting with others at old Rebel base

"We are here because we've seen this before, and we now we must prepare."
"What we are doing could get us all in lots of trouble, the New Republic specifically banned systems from arming ourselves."
"They are free to come and try to stop us, I sense the intent (Leia senses Ben) of the First Order, there will be war, and soon."
"Very well, we can begin immediately fixing up the old ships we still have from the rebellion."

These are not great, I'll confess, I'm no writer, but they do quickly convey the situation to the audience and how things can play out the way they do.  Give parallels to World War II and appeasement process.