S.
Hi H.,
As much as I hate to admit this....I sucked my thumb (at night only) until I was around 13 or so. My teeth are fine, I never had braces. I know a lot of moms want to stop their kids from sucking their thumbs..but my problem is the pacifier, I'd almost rather it was thumb sucking.
I think she will grow out of it (hopefully before age 13 :) )
If she's not doing it too much in public, I'm not sure what it could really hurt as long as the dentist doesn't see a problem growing.
I hope this helps,
S.