I totally and absolutely adore this charming name. Not only does it have a beautiful meaning (my beloved, sign) but it fits both a young child and a mature woman. I think not absolutely sure but it is on my list of names for a daughter.
This would never be used as a given name in Italy. It's like an American naming their child "darling". However, Caramia is sometimes encountered as a last name. I personally think it sounds a little corny as a first name.
This is quite tacky to anyone who knows Italian (and if you don't, its quite easy to figure out what these two words mean) its a cute idea, but maybe just making her first name cara and her middle name Mia is better. Although I can't say I like the name Mia as a full name. Yuck. Yeah, maybe don't use this for a real child.