Make my 18th bday ballin?

Ight so here's the deal. Where I live, downtown is where you go to do ANYTHING bc everywhere else is just woods and all there is to do is go muddin' and stuff. What's going to be happening is me and 4 good (girl) friends are goin to the beach, then headed out downtown for the night. When we go out that night, my bf and best guy are meetin up too. About 3 of these people are underage so idk if they could get into a bar with us? I mean, there's a lot of scenery downyown so there's lots of free places to just chill down there, but I wanna make this night unforgetable. Please please any suggestions. I would love to go clubbin but I donf think the underage ones could get in? I have no idea what to do to make this "party" incredible. Im up for anything.