I am also 16 and I never had any female friends either before this school year. It is really not as hard as you think. Just try to be friendly and make small talk with some of the girls in your classes. Keep in mind that girls are just people too, not some mythical creatures, and they like to talk about a lot of the same stuff that guys do. Most will probably be nice to you, and if not they're not worth your time anyway. Also, try joining clubs where you will be able to meet girls with similar interests as you. That way you will have something to talk about with them right off the bat. The secret is really just to be friendly and put yourself out there and I'm sure that you will make some new friends.