joint bach weekend - need advice or tips

Me and my fiance planned a joint bach trip for this weekend. we are both very type B “we will figure it out” type people. But Now i am so anxious. We have a plan to stay at the house and basically drink and play games. Now I am stressing that it’s not enough and I should have pulled myself together and planned a big themed thing like all these people do now a days.

It’s like 18 people including us, the wedding party and some of their partners. All of his friends know eachother and all of mine do but the groups do not know eachother. I’m nervous is gonna feel awkward. We are all also in our late 20s/early 30s so we haven’t really partied like this in a while.

any advice or tips?