My first thoughts wasn't
Wendy's and I wouldn't have thought it if you didn't point it out (I'm not American tho). My first thoughts were either
Wendy Darling of
Peter Pan and
Wendy the Good Witch of
Casper. Both good associations really, nothing negative, but a little dated. It's one of those names I want to like more than I do.
Apparently it comes from juvenile "fwendy" which sounds just incredibly American so it really does not make me think it less of a name. Kids don't say "fwendy" here lmao.
The problem with names like that is your kids might just end up preferring
Gwen and you might just have to live with that. You wanna name her
Wendy, name her
Wendy. I don't see a problem with it, personally.