a little OT, OP, i love your dd's name-Aventine! Just curious, do you say it "Aventeene" or "Aventyne"?
BOT
we say "vulva" because that is the term for what a child actually sees, and it's a nice blanket term for all the different parts, which i named as dd got older (around 2) She knows now, she's 6, that she has a clitoris, vulva, vagina, urethra, and anus (which she thinks is a gross word and so will only call it a butthole, lol)
eta
my 11 mo old is learning about his bits, too, and i say "penis" for the whole package at the moment. will name testicles as he gets a little older.