I was invited to a halloween party, but i dont know if i should go.

hi!

im 21, and i dont have very many friends due to doing college online. an old classmate reached out and invited me to his party, which i was super excited for and have been planning my costume since. there will be alcohol, and while i dont drink, i wasnt aware a majority of attendees are 18-19 years old.

my old friend is also 21, and other than a few other 21 year olds from my HS, the rest seem to be 18-19. Would it be weird to go? I dont really see what i have in common with a high school senior, as a 21 year old in college. thanks.