First of all, Let me Just say that I am a girl with a what is considered to be a boys name and I have Never regreted it, I love having a name that not every other girl has, That being said I do understand that not every little girl would be as happy to have a "boys" name as I am.
Okay, now that that's out of the way, One of the names that has been on my mind lately is Gibson. I think it would be Lovely on a girl of any age. maybe Paired with a more natural MN Like
Arianna or
Elia. what do you think? and please remember that this is all just a matter of Taste.