Bachelorette Party Rant

So my best friend of 13 years is getting married in June 2018. The maid of honor and other bridesmaids have planned the bachelorette party for March in Mexico! My son turns 1 on April 4, 2018. I do not want to go to this bachelorette party. I am the only married one and the only mother of the group. I want to support and celebrate my friend. But seriously, I don't want to party in Mexico days before my son's 1st birthday. I can't afford it and I don't have the vacation days either. Am I right to be a little upset?