I figured someone here might have some ideas for finding some math community for her. Preferably in-person (in Washington), but virtual could work too. Thanks for any suggestions!
Get her a tutor from Preply (you can find incredibly affordable math tutors in foreign countries) and have them work through past contests.
Are there advanced classes for her to take in your school district?
Then there's math competitions.
http://hub.wastudentmath.org/Competitions
Wish you & daughter success.