My first drinking party is tonight?!?

so ive never been to one before but my friends do it all the time. i am 16 ik its illegal and bad but im going, so dont waste time with that :p ik the responsiblity and everything , like dont leave ur drink alone keep a sober friend etc. BUT my friends tend to group together and leave m eout sometimes so im worried ill be there without my friends. my friend is bringing me so i do have someone to show up with... but who knows, she knows how to party so shell prolly just run off and bam im all alone. the host of the party i am somewhat close to.. but not enough to feel confident with just him or something i really want/hope my friend will stay with me, but her other bff hates me so i feel maybe theyll go off together,, HELP!!! :):):):)plus i have NO idea if were suppposed to bring our own drinks.. im not cause i have noeone to buy them for me.