I second the rec of "Mona in the Promised Land." It's one of the few books that I feel like "gets" ideas about fluidity of ethnic identity. Mona is an Asian-American woman who feels strong ties to Judaism, and converts. But it's not about her journey away from Asian-ness towards white Judaism. It's about how she does and does not fit into Asian-American ideas, and ways she does fit into a certain type of Jewish idea and uh. Stuff.

Except it's not YA.