Yay another tall flyer! I'm 18 and flying in college now, but when I was in the 8th grade I was 5'5 and about 105lbs (Fast metabolism, I eat like a horse).
Don't go on a diet, you'll drop tons of weight but you'll start eating again and gain it back. I did that in 8th grade and to this day I literally am scared to eat because I feel like I'm too big to fly. That is not the case though(: Do you have a wii? Something that helps me was eating like 1,500 calories a day (which is healthy!) and playing Wii fit and Just Dance. Especially the new Just Dance 4, it has Just Sweat and it's INTENSE haha.
Anywayyss(: You're not too tall, if they aren't like "Lets put her up!" Then simply ask the coach to let you fly. I didn't ask for 2 agonizing years, and the second I asked the coach basically told me that she thought I didn't want to -.- So yeah, just ask.
Keep stretching that heel stretch and scorpion, and google "scale" and "bow and arrow" once you get the hang of those(:
Lvl 6 flyer!(: