This is exactly what is wrong with society - one size fits all answers to everything.
There is no correct age for anything. It all depends on the person in question and their personal maturity level. That is why we set minimum restrictions, but parents can choose to ignore them. 17 is perfectly reasonable minimum restriction without parental consent.
1: If you think your opinion is fact, then I will ignore you. 2: If you butcher the English language or abuse Netspeak, see #1.