One is competitive, one isn't.
It depends on the teacher and how competitive they are.
Pre-competitive gymnastics is basically working on technique and conditioning, and getting you ready if you decide to take up competitive gymnastics. Many places let you compete in competitions. After some time if the coaches think you are doing well, they will recommend you to join the competitive group.
Competitive gym is where you do competitions and try to win amid a group of other gymnasts. Compulsory gymnastics is has levels of gymnastics that you must complete in order to qualify for some competitions.
There are no belts in gymnastics. There are competitive levels, but there are no belts. If you're asking what level you have to be to be competitive, that would be level 4. To train for the Olympics, you must reach level 10.
The school team, a separate league, or a competitive team.
Many competitive gymnasts are older than 12. All of the gymnasts that compete in the Olympics are examples of this.
4 and 1/2 (ish)
not all but most are! and theyre not called gymnastics players theyre gymnasts!
A trapeze. Technically that might not be considered gymnastics though it is obviously very closely related because it is not a competitive discipline or aparatus within gymnastics.
For fun, friends and fitness - no. For a competitive career - probably yes.
She stared when she was 3. She started because her parents said she had to much energy around the house.