Totally agree with Carron. I cannot see any problem with holding a party for 15/16 year olds where there aren't large quantites of drink involved and the drinks are carefully chosen, and if there is a responsible adult on the premises, e.g. parent. It makes them feel trusted and like young adults.
Better that than drinking with your mates in the park or other places and knocking back voldka, cider, etc.
Forbidden food always tastes better!!
Yes, we were all young once, but we didn't all drink in the park with our mates.