I don't there are three reasons why.
1The tar that builds up in your lungs.

2This is the main reason. The THC in pot hinders you hippocampus( or memory/learning) part of the brain. This means if this THC builds up it is harder to learn or be motivated to learn in school, or other activities. Me being 14 and a straight A student, planning to be an astrophysicist I want to learn as much as I can.

3 Also pot affects the pituitary gland which controls growth in your body, and I'm at the age where growth happens the most.

Pot may not kill you, or be as dangerous as other drugs, but It will play a major role in your life if you are an avid user. 

 You know many scientists smoke weed. Francis Crick, the man who discovered DNA experimented heavily with LSD and weed. It's funny how you said you wanted to be a astrophysicist because I'm planning to be a theoretical physicist. It's basically the same thing only you're dealing a lot more with singularities.

May I recommend to you A Brief History of Time by Stephen Hawkings.

 Yeah, but I just don't want to chance it. I need  my full attention in school.

Thanks for the recommendation too.  

Nope, never been interested in it, so never tried. Simple as that.

As long as you're not sitting in class stoned out of your mind everyday, THC won't affect learning. Memory inhibition only occurs while under the influence and has never been shown to cause any long-term effects. It's like when you drink too much and wake up the next day not remembering the night before (short-term memory loss). With weed it's not nearly that extreme though. It's more along the lines of, "What were we just talking about?" I've never had a blackout night from smoking, but there have been a few parties I don't remember going to from drinking.

I'm not sure about the pituitary gland, but it's best for young people to avoid any substance until they're mature enough to handle it anyways.

 I wouldn't know about that. LOL

Well..... it sucks lol

I figured you wouldn't, I was just trying to relate it to something with less stigma attached.

On the bright side, it makes gummy bears and Doritos delicious

Ah yes, the 'munchies'. Gotta have skittles, wotsits and pickled onion monster munch.

There's only one thing in life worth smoking, that is a fine, expensive cuban cigar, on a cool ambient evening while laughing about how rich you are, which i was doing last night