From reading her letter which I just posted, it appears there were 4 boys and herself at that party. Unloess one of the boys was her brother, she shouldn’t hare been there.
The supposed party which probably never happened but was a composite of the many parties she went to.
Four high school boys, a lot of alcohol and maybe drugs, no parents in the house and one 15 year old girl.
What kind of “party” is that?
There are a number of accounts of further statements where she accounts wearing a swimming suit under her clothes.
A young girl going with four boys to a private home, with no mention of swimming involved, and where drinking is going on, wears a swimming suit under her clothes for one reason that comes to mind.
She intends to interact with others but does not want to have clothing easily removed for interaction other than what she plans.
Yes, there were four boys at the party and she was wearing a bathing suit. Based on the pictures of the kinds of bathing suits those girls wore, it was probably a bikini.