I am also watching. I competed for many years. Although most of the time that I was a competitor, the levels were different. They were called "classes" and went from 4 to 1, the elite. Shortly before I stopped competeing they changed the levels to 1-10 and I was competing at level 8.
I coached for several years after that. I did work with some of the team girls but I really preferred to work with the very young kids. Gymnastics is a lot of hard work, but there is a HUGE natural ability factor as well. When I was coaching, I could tll with in the first few classes whether or not a child was going to be strictly a recreational gymnast, or if they were going to progress through our program. The girls that have the natural ability learn the basics at lightening speed, the are naturally coordinated and poised, they are naturally strong, they are naturally petite.
I don;t know if I buy the theory that gymnastics "stunts" growth to the extent that it's blamed for stunting growth. To be successful, gymnasts need a specific body type and I think that it's more genetic than anything else. They tend to have narrow hips but broad shoulders and they are short. I think the extensive work out schedule can delay puberty, but I don;t think it will actually prevent you from getting taller if that is what you are genetically programmed for.
My DD is 2.5, I plan to put her in a parent participation class in the next few months. But, it will be DH that brings her. I think I would not be able to resist the urge to "coach" her and I want her to enjoy it, not hate me.

If she loves it, i will support her in it, but if she does not and she would prefer to play ice hockey, that will be fine with me too.