How would you feel?

Hey guys I dont quite know where to post this and sorry this is so long but I want to know how you all would feel... so I am going to be a bridesmaid in my BF's sister's wedding this May. We haven't always been super close, but as of late, we have grown closer because we are both in school and I watch her kids (for free) 2 times a week (a long with my own 16 month old) while I'm on break from school. So I was added to the wedding party back in February, after the 3 other bridesmaids had already started planning the bridal shower, bachelorette, etc. So one of the girls texts me to inform me of the bachelorette weekend. A night out going to bars in NYC. The bride just turned 21 and barely drinks. I won't be 21 until September so therefore I can't go (even though I'd love to). Anyway, after one bridesmaid ends up getting kicked out of the wedding, the other 2 remaining girls pick a new plan for the bachelorette, but I haven't even been told what it is?? I suspect they are still going out to drink that's why I wasn't invited? Now I would never say anything to anyone... but I can't help but feel kinda hurt by their decision. Its supposed to be a surprise for the bride and I know it's about what the bride wants... but I feel that it's kinda shitty to plan something that not all of the bridesmaids can attend. I'm not trying to make this all about me, just needed to get this off my chest.