what do i do? i dont want to be left out

i’m going to an amusement park with friends and we were supposed to go tomorrow but we have to change the day. the problem is i need a chaperone because they have a policy that if you’re under 18 you need to be accompanied by someone who’s over 21. i’m the only one who isn’t 18. switching the day means i won’t have a chaperone because i doubt my dad will agree so what do i do?