Like the title says I just started Kingdom Hearts and I don't know what the game prepares for me so could anyone say some advice or reccomendation?

PD: I choose the shield and eliminate the sword

There's not much advice to be given but you should give a particular attention to the story because it gets really complicated in the next games.

That means that you will have higher health and lower attack. Naturally. Anyway, you'll be on "Tutorial Island" for an hour or two. I suggest you level up a bit. If you reach level 10 before leaving the island, you will probably never have to grind. Mind you, grinding isn't as bad in Kingdom Hearts as in other games, since after the first few hours, you can go back and visit old worlds for XP and treasures.

I am already on Tranverse Town and I'm level 6

I just beated Tarzan's World and I'm level 18, Donald 16 and Goofy 21

PD: I HATE those big and fat heartless >_

This!

It´s easier on paper than on action

Doh!

I know it wasn't the best election but my Sora can resist a LOT of attacks

Um you BARELY started???
Damn you are going to have some fun with it especially the 2nd one which is a golden masterpiece IMO dude its a good around fun game BUT BEFORE YOU PLAY THE 2ND ONE PLAY CHAINS OF MEMORIES OR ELSE YOU WONT KNOW SHIT!!!!TRUST ME ITS ON GBA OR PS2