Personally, I wouldn't consider myself as a nerd. I would consider myself a geek (Yes, technically there is a difference). I am still an avid gamer, maybe little too much (I've been playing Minecraft since it came out) and I do actually do some good things. However, in the same social sense, I am considered lower on the popularity scale. I have never been to a "high school party" but would probably not go if offered. I have aways hated pep rallies and dances too. But, I'm happy with the way I am. I would like to consider myself one of the most mature people at my school.
See, here's the issue with people like you, hydra, and myself (at one point at least, I'm better about it now, but I still struggle with this). We all think we are more mature than everybody else. We have this built in superiority complex just because we probably were (or are in your guy's cases, I don't deal with high school bullshit anymore) better/smarter/more mature than that PARTICULAR group of people. Thus, since we think that, we don't even bother trying to improve ourselves because, I mean why bother? You're already smarter than everybody else your age, why try to improve that?
Well let me shatter your little sense of security in that and break it to you the hard way. You're probably a dipshit. I mean we all are in one way or another right? There's no sense in thinking you are more mature or smarter than "everybody your age" because this is the ONLY point in your life where you will EVER be forced to deal with people that are of your same exact age and educational experience. Once you get a job, go to college, get out of this bubble of people you are forced to see and deal with every day, you will realize that there ARE smart people out there. VERY smart people out there, that with two sentences can make you feel really fucking stupid about any topic they want. There are VERY experienced and mature people in different aspects.
Do I still think the majority of people aren't as educated as they should be? Of course. However, I also do think that even the most worthless of people have something to contribute to society. Those people you think are "Immature" at your school will probably grow up and get decent paying jobs that put food on the table, or one of them may cure cancer.
My point I'm trying to make is that for the sake of your own self esteem and emotional security, I can tell you first hand that a little bit of a superiority complex can be healthy and make you feel like you're worth something. And god knows feeling worthless and insecure is a very shitty feeling. But don't let it get to your head and have you make false assumptions of people before you actually get to know them. Everybody has a story, everybody is smart in some way, and everyone has a purpose in life. We never really know what it is, but that's why we keep living and being the best we can be, to hopefully one day find out or accidentally fulfill that purpose.