What do i do in this situation?

i told my mom i would go with her for a BBQ and fireworks but my dad's family does an annual mini-golf tornament, and i didn't know. my cousin told me that i really should go cuz its a "family tradition" but then told me to not be pressured to make a decision because i should be able to go where i want to go. i feel like no matter what i'm gonna dissapoint someone with the decision i make because i know my mom will be rly upset if i don't go to the BBQ and watch fireworks like i said i would but if i don't go to the mini-golf i will be dissapointing all my cousins and ppl tht are going to the mini-golf thing. i dunno what to do cuz i know my mom will get upset if i go wit my dad but i know tht my dad and my aunts family will be dissapointed if i don't go, cuz its an annual family thing. WTF