Is it normal that i am overconfident?

Get over yourself. School is full of dumb asses. You're making yourself look like one also.
Chill out..

Sounds like your confidence is over compensation for the criticism you receive from other people.

this is usually a normal reaction for many people who feel judged or criticized.

Youre not being smart by allowing their comments to get to you. theyre outsmarting you!

I hate you, dude. Be a nice person perhaps?? (Sarcasm) I could imagine my fist pecking him in the face. I mean who says that!?

Normal. It's you putting yourself of the defense. Warning, my brother had people ripping on him at school so he did the same thing you are now and became somewhat of a 'bully'. He lost most of his good friends because of the way he was acting and got people who were no where near as loyal as his old friends. Now, he seems to feel like he has to stay in that mind set and he can't hold down a job because as soon as the boss orders him to do something, he goes nuts. He's almost 30, left high school years ago and now had 2 children to provide for...
I would say, choose wisely where you apply that confidence and how. There's a time and a place for everything. Learn who deserves your respect and who doesn't.

if you were overconfident you wouldn't need to ask is it normal