I have to admit that I am a bit surprised. St. Louis is a significant metropolitan area, so I would expect some presence. However, I guess I have to factor in that it is Missouri. Anyway, it may be useful to get a few pointers from your daughter.
I used this as a search string:
transgender resources st louis missouri
Have a look at the results. Some may mention resources for parents and kids, but mixed in may be things for adults…