OP, your birth experience is more important than the feelings of whoever else wants to be there. You need to feel safe, calm, and relaxed. You should ask your caregivers for advice on what to say, because they get this issue all the time.
I'm a MIL and a former doula, and while I would love to be present if my DIL ever has a baby, there's no way I'd want her to feel pressured to have me or anyone present, if it wasn't what felt good to her. I'd be sad to not be there, but I'm a big girl, and I know the birthing mother's feelings are what matters.
A compromise might be to have MIL wait in the next room, so she could be there, but not THERE in your hooha.
