I'm over 30, and it worked for me.
The caveat is that I haven't had children (the surgeon mentioned the best results for stomach lipo are on non post-pregnancy stomachs). But I always had a "breadbasket" along my lower belly.
You can always go to a plastic surgeon's web site and view before and after photos of tummy tucks v. stomach lipo. Again, though, during your initial consultation with the surgeon, she'll advise you best.