Well, great - you're a musician. A lot of shy people are involved in music, it's a great thing to use to find your crowd. Does your school or community have a band or orchestra you can join? I was in a band at my high school and it was terrific for meeting friends.
It's fine that you don 't wear makeup. And just a tip - lots of boys don't like makeup on girls, so if you don't like wearing it, well - don't then!
It sounds like you're just shy. A lot of people are shy and I think what helps in that situation is to find things you can do with other people where you can just join, and other people just join, and you end up together. Because there's an activity, there's not so much pressure to talk, and there's also something to talk about. As you get more comfortable, you'll find it easier to talk to them in time, so you just keep going even if it's a little awkward at first.
Another activity that's great for you to consider is theater. If your community or school does plays or musicals, that's a great way to meet people. You'd think only outgoing people would be involved in theater but actually, many shy people are drawn to acting because they can pretend to be someone else, which makes it easier for them to be loud or talkative or whatever. And if you don't like being on stage, stage crew is a blast - costumes, sets, lighting and so on are really fun and you can learn with the group how to do it.
Be patient with yourself. Many girls and boys your age are shy and self-concious and it's also just a generally tough time. When kids are little, friends are kind of determined based on who's in your classroom at school, or who lives on your street. As you get a little older, it has more to do with who has things in common with you, and making the transition from being a kid to being an older teenager is tough. It will work out and you will find your crowd. Just do what you love, and you'll attract people who will see you enjoying yourself and doing well at your interests.
