i am by no means an expert, but in my opinion, and from what i've seen, it doesn't matter how tall you are. you can do gymnastics at any level at any height. there is a gymnast here on CB who started a post about gymnasts' height who is 5'9" and a level 10 gymnast.
don't ever tell your dd that she is too tall to do gymnastics or let her coaches tell her that!! if she loves it and is doing well, let her keep doing what she loves and it doesn't matter what anyone says.
when i was younger i went to gymnastics and they basically said i could never get anywhere in gymnastics.. that i was "too tall" and my mom believed them and made me stop going. i was devastated... i loved nothing more than gymnastics, and that effectively crushed my dreams. i didn't even try to do gymnastics 'til college because i figured i just couldn't do it.. that i had the wrong body type and it wasn't possible for me. however, my old coaches couldn't have been more wrong!! i'm 5'5" and i started going to gymnastics a few years ago at an adult class, and i progressed very well and even made it on the prep op team. i am certainly not "too tall" for gymnastics like they said. my coach is 5'7" and she was a college gymnast.
being shorter and lighter can give you an advantage in gymnastics and make it easier to do certain skills, but in my opinion, that's where it ends.
there is NO such thing as being too tall to do gymnastics!!!