How can I become more girly?

I will be entering high school next year and I am going to a middle college on a college campus. I was home-schooled for middle school and I have always been shy and quiet when I am anywhere but home and with my close friends. I am worried about making new friends and lately I have been thinking about wearing skirts. The problem is I don't have any except a few simple longer skirts for church, and I have never cared about fashion before. I still sort of don't. How can I try skirts and stuff without seeming weird in front of my family and friends? My sister isn’t supportive and my brother would probably make fun of me (that wouldn’t bother me since he annoys me every second possible anyway). Also, one of my close friends doesn’t care about fashion and loves the band Simple Plan, while my other close friend is kind of girly and crazy. I would feel weird going to anyone about fashion or stuff like that; what should I do?
If it helps, I am 13, tall (5’ 6 1/2”), slim, and pretty flat chested. My hair goes about to my upper back and I have bangs. Also, since someone cut my hair wrong, I have a bit of hair on both sides of my head that I am working on growing out that is about 6 inches longer than my bangs (enough to push behind my ears but too short to go into a pony tail). My hair is light brown and blonde streaks have starting showing up naturally, I usually wear it in a low pony tail; my eyes are hazel (goldenish) Also I just got braces and a herbts appliance put in my mouth.

well first things first. people aren't going to like you because you're girly, real people are going to like you for YOU. don't feel you have to change who you are to impress others... if you want to wear a skirt just for the heck of it, then go out and but a skirt! I don't think your friends are going to make fun of you. and also, I think it is a good idea to get advice from your friends and to go shopping with them because I'm sure they'd love to help.