how long should I wait?

I had sent an e-mail about a month ago asking what dates were good for my BMs to go dress shopping...they told me and I made a schedule of appointments.

I sent an e-mail last Thursday with the appointments and asked who was coming, but I haven't heard back from maybe half of them. How long do you think I should wait before texting them and saying hey could you let me know?

I don't want to sound angry at them, because I'm not; I realize they have better things to do. But the first appt is in 2 weeks so I want to make sure they know!