Questions: Family & Friends

Hey, hope you had a great Christmas. I had a think and realised I was a bit hasty in turning down friendship. I think we have a lot of common interests & it would be fun to hang out and get to know each other as friends. Think enough time has passed now since we met in a date context. What do you think?

So my girlfriend is mexican, and apparently she has a tradition in her family, once a year, to play a traditional game from her culture (from some original mexican tribe) where all the men of the family and their gfs/wives play.

The men have to stand up in boxers, legs open and hands attached behind their back, and no cup and the women of the other teams kick and throw tennis balls, soccer balls, basketballs at their groin from a distance. The last man standing wins and doesn't have punishment, the first one to lose has no courage and every other women from the other teams gets to kick his groin. Apparently it was originally played with rocks instead (ouch!) and was made to compensate for women having periods and going through pregnancy.

So 1st place no kick, 2nd place kick only from 1st place woman, 3rd place kick only from 1st and 2nd place woman, etc...
I am scared to play, apparently this year its next week and she wants me to participate for the first time, apparently all men play and those who refuse for no good reason are made fun of and seen as having no balls, often rejected and not seen as a good marriage fit.

Also she says I'll have more endurance because I'm younger and she plays basketball so she has nice precision and could made the other guys fall before me, but all of this still feels weird to me.
Should I still accept because I love her and she does everything to me, to show her I would do anything for her and get one step closer to her parents' approval?

Like they tell what day it is and how much longer it is until then.