I am very excited to be a BM for one of my good friends from undergrad. I am not able to attend her bachelorette party (at Harry Potter World! Super awesome!) due to conflict with grad school and expense. I feel bad because she's a dear friend, and it sounds like it will be a great time! Should I try to send a gift in my absence? What is the etiquette for when you have to miss a pre-wedding party as a bridesmaid?