threesome with my bff/her bf: awkward?

i dont really know the best way to put all this into words, but my best friend has invited me to

have a threesome with her and her boyfriend. the idea excites me because i’m single right now and not interested in anyone in the vicinity really, so at first i was totally down!

but one of the problems is that i’m a virgin. i know and trust these people and i know they’ll be patient and make sure i’m comfortable, but i’m afraid that my inexperience will put a damper

on the evening?

my other major issue is that i’m not a very no-feelings-attached person typically, so i’m afraid to catch feelings for one or both of them because i’m pansexual and poly, so i wouldnt be opposed to a romantic relationship with both of them, but i’m afraid of making things awkward.

has anyone had an experience/problem like this?