she’s 12. Let her do horse riding with her best friend.
if she is good at dance it won’t be long before it takes over her life and she has to pretty much give everything else up anyway. Let her do it now while she has the chance.
i rode and did ballet/gymnastics as a kid. Never noticed it have any adverse effect physically, it was more I couldn’t spare the time, especially as school ramped up for GCSE’s. My flexibility was always fine, and riding needs hip turnout- although toes are in in both riding and gymnastics it’s not the direction of the feet, it come from the hips.
it may be difficult at first as she will be stiff from using different muscles, but as with everything it will ease.
i gave up a lot- no can’t come shopping, got dance practice. No can’t hang round after school, got dance. No can’t come to x, y and z, got dance practice. Even as I got older and friends went clubbing and the like it was can’t drink, got to be home as up for dance etc.
long term too if she injured and ballet doesn’t work out for her as a career, will she regret having given up social time and other activities?
let her try it and see :).