I hate being short
I am sorry to hear you are feeling upset. What do you hate about it?
I just get so jealous of tall people.
If you are unhappy with your appearance, then you could talk to a therapist to work on your self-esteem. Or you could take up a hobby that makes you feel proud of yourself so you aren't always feeling jealous of others. Redirecting your energy to something productive would be a better use of your time.
Why don't I just wait till I grow up and not do anything?
You should do just that and be patient with yourself. You will be happier if you can accept who you are at this point in your life.