Help relationship (trust?)

I need help

Hi I’m 17 boyfriend 19 we live in different states until this weekend so he wanted to spend time with his brother for one last time before he moves in with me which is great but then he said there might be girls( his brothers friends ) there and one room that they all have to share ( wth? ) so I’m like “ okay..”. But then he takes shots of alcohol which he knows he shouldn’t do at this age then he says “ oh there’s two females here “ Then later he’s like ( like 4 hours later after he’s sober I guess ?)“ oh there’s no girls here only 7 guys there wasn’t any girls here when I got here or at the park or when I got back “.. so I’m like “ are you lying to me ? Because earlier you did there were girls “ ( I’m fine if there was but I wasn’t comfortable if they were all in the same room because he doesn’t know them ) Then. He’s like “ I’m not lying I thought there were when I got there but there wasn’t “.. (?) I’m like “ okay…?” I’m honestly losing trust because I don’t know if he’s lying or not I trust him but not this situation. I don’t know if he’s lying to me