Looking for some advice? ?

Difficult choices.  It SOUNDS like you are more mature.  But not necessarily either.

Part of going to school is learning to deal with people, differences, social, pressure, changes, and different levels of maturity as well as economically.  

So if you feel irritated by your friends, or classmates etc, then maybe you need to figure out what the underlying situation is. 

Loud does not make them bad.  Immature in what way?  Realize this is High school. These are kids that you are going to school with.  You are as well.  And sure you don't need to be loud.  You don't need to act the same way they do.  But then maybe learning to be a leader.  Learning to help control the situation you are at.  Teach your friends to be more calm? (or whatever your issues are).  That will prove your maturity level, rather than being upset or just irritated.

Find different people that may be better suited to your behavior, lifestyle, choices, maturity level etc.  Sometimes that means outside of school.  Perhaps a sports program through the local clubs.  Perhaps finding friends at a church.  You make the best of your school life. The choice is yours.  Not theirs.

It sounds like you have matured sooner than most of your friends. Perhaps you should consider trying to make some new friendships with people a year or two older to match your maturity.

Let it go. It won't matter in two years. Just do your own thing. Live your life and start planning your future. If you have an "I don't care" attitude and you put out positive vibes people will start flocking to you like sheep. Your negativity is just making things worse in the long run. There is no reason to get upset over these loud immature kids because after high school you will probably never see them again and if you do its typically on your own terms and you can walk away. The best advice I can give you is be your own person and focus on what makes you happy.