gia has two older siblings and one younger, she's 27 so any age fitting in one of those slots would be fine by me. they have a big italian family, a typical and traditional one, and their mom's brother is actually involved with organized crime so when she got married to their dad, it was both because she loved him but also because she wanted to distance herself from that whole scene as much as possible. sometimes there's family friction or drama as a result, but i haven't really played around with that in game yet! she would also get built in maternal cousins in valdespino (the mob uncle's son) and trapper. as far as their upbringing, i have it that it was all pretty normal with nothing out of the ordinary (except ya know, for the whole sopranos thing lmao)