With 18 of us I doubt we will be bored. There is a beach, which means we can swim, we have copious amounts of alcohol and plan to do a lot of activities. I'd say it sounds excellent.why would you come to the bay for schoolies? go somewhere fun where there is actually night life..
and as far as beach parties only little 15 years olds invite people to go to fly point parties.
You will be guaranteed to be bored out of your brains!