I'm thinking of deciding between attending a new friend's bachelorette party instead of my cousin's wedding
Why would you decide at the last minute that you'd rather attend a friend's bachelorette party instead of your cousin's wedding.
There is just somethings that are more fun at a party than a wedding.
If you've already committed to going to the wedding, it's too late. Backing out like that is rude.
I wonder if I can attend both. What do you think?
You can't really go to both so it is best to come to terms with the situation and try to enjoy the wedding. It is expected that you enjoy yourself at a wedding.