Party troubles

My matron and maid of honor (who happen to be my sisters) are throwing my lingerie/bachelorette party. One of my other bridesmaids have been asking about dates so they can plan when to come in town, but my MOHs were waiting in a date to be set for the bridal shower. I’m starting to stress out because the bridesmaid is hounding me about flights saying she needs the dates and that flights get more expensive the longer you wait, which I get but it’s out of my hands!
She told me I need to just plan it or get the dates from the MOHs but it’s not that simple nor is that polite. I wasn’t stressed until she starting texting me and now I think I’ve upset her. I told her we are waiting on the shower date to be solidified, which should be this week, and then planning a date from there. She hasn’t answered me which isn’t like her.

Idk what else I can do! The wedding is August 8, which is 58 days away. We got engaged two months ago and the first month we didn’t even plan anything because we were too busy with work and our dance season.
Any advice??