how can I get along with people are to immature?

First of all, don't worry. It's perfectly normal for good friends to have different personalities. :)

If this childishness is causing tension between you and your friends, I'd suggest you focus on what you do have in common with them. What hobbies do you have? What TV shows and music do you like? Find a common interest and take it from there.

Being mature does not make you "lame"! It's important to just be yourself. If you spend your teen years pretending to be someone you're not, you will regret it when you're older, so be true to yourself. If your friends try to pressure you into changing your personality again, try asking them, "why can't I just be me?" It might not seem like a very complex question, but it might help them realise that trying to change who you are is wrong.

Think back to how you became friends with them. You mentioned that you pretty much get along, and that's good! So, why do you get along with them? How did you become friends in the first place? There's obviously some reason you two can get along well, so focus on that too.

So, long story short: find common interests, remember why you are friends in the first place, and be yourself!

Good luck! :)