Isn't that a contradiction?
They can't be stars at 17, but they cant be stars if they are only just hitting the adult scene at 18 unless of course there is something unbelievably special about them which is rare.
Or of course like so many young looking models they are being pedaled out on their merits with their age being wound back to suck in the morons that believe girls at that age are that accomplished in the bedroom at such a young age.