Taera,
These are great replies. Many of us are older so can talk from years of experience. I am 40 and I STILL make mistakes (social ect...), but I know that it is the way things are and that things will be ok.
My High School years were the lowest in my life, I didn't have alot of friends either, I was more nerdy I guess. I remember asking a girl to a dance, and she started crying, I found out years later she didnt know how to say no, though it messed me up then, when I got older I wondered why she just couldn't say "No, thanks". So remember this, everyone your age is learning social skills, some will be better than others. In school we are told that not making mistakes is good (ie get good grades), but in "real life" mistakes are the only way we better ourselves (well as long as we learn from them
).
As Rutha said, if you like computers, perhaps you can go take some classes at a community college (we have fast start or some such that allows HS students to take college class's). Heck, don't limit it to computer courses. The dancing idea is a great one, you will get over being shy when you dance with older women taking courses. My Last idea would be perhaps look into something that you would never think of (or not see yourself ever doing). If you like reading books, join a book group that covers a complety different topic from what you enjoy...
Good luck friend