Dude. DONT GIVE UP. Everyone has a dream and god forsake, its my dream too. I've been cheerleading for three years but never competed seriously and it's all I want. DONT GIVE UP. When you stretch, make sure they're good stretches. Stretching is good and if you do it often, you can get all of your splits. I know this might seem harsh and please don't take this the wrong way but YOU CAN NEVER BE "TOO BIG" TO BE A FLYER. Fight for your dream. If you don't . No one else will.
Convince your mother that THIS is what you want. That it's your dream. Maybe she'll understand. Try to negotiate with her and tell her how much this means to you. If its money, You can always attempt to talk with coaches about fees but make sure youre going to a good gym! don't spend money on a gym that isn't focused on your success. It's okay, I've been there. Maybe your mom with be more convinced if you got all the flexibility you need and all you need is the next step for training in tumbling. Stretch well, don't overstretch too much and injure your muscles. But ask your coach for pointers and advice. Hopefully she'll understand.
P.S. DIET is important with flexibility. If that makes sense? Your body has to be up for it. Eat healthy and exercise/stretch. Never stretch on cold muscles
Never ever give up hope on this dream. I had the same dream when I was your age. My town finally got an all star team, right when I was about to give up. But, I didn't. I am a national champion, and we have come runner up at the summit. I couldn't do a cartwheel when I started, now I'm doing back tucks. Please don't give up. ?? You will regret it.
You can still do All-Star, but they may put you in level 1. Also, what do you usually eat and drink? Water will help you gain some flexibility, and I'm sorry that you haven't improved. Have you gotten your jumps yet? Do not give up because it took me awhile to get to where I was. You will get there!
you should never quit. you said youre on the school team right? thats closer than most people. just keep your head up high and strive to succeed. try yoga for flexibility.