i am 21 and i was lucky.
when i was 19 (late feb 2001) i got a used n15 pulsar 1.6 lx or whatever (base model). my dad put the policy under his name but it still cost $2500. renewal in 2002 cost $1600, which was pretty sweet.
got my skyline r33 gts-t in dec 2002.
i found out only when i was trying to get my skyline that the poliy wasn't under my name, but i sent a letter to famous saying i had been a *named* driver on the policy since feb 2001. they luckily accepted it, they didn't have to. technically i had 0% no claim bonus, but they accepted 30%.
so in a way, i was in your boat, but i wouldn't count on it working twice. it was kinda do or die for me cos it was after i put a deposit on the car.