great dane meet up question

[schelmischekitty]

i found a group here in atlanta that does great dane play dates i think once or twice a month.  last month the coordinator told me she had 15 GD's show.  i'm worried though that diesel is still such a puppy that he might aggravate the dogs that have been going for a while, that or just completely run and hide.  does anyone have any tips on how to get him ready to go to the one after the one on dec 2nd? when we go should i keep him on a leash until i figure out how he's going to react to other dogs??