To allow her to witness-or not?

Today I hit 34 weeks.  Six weeks until my due date, but really only 3 weeks and they won't stop me if I go into labor...or if I go over 8 weeks. But we'll leave THAT possibility alone. With Baby #3 fast approaching there's been a lot of baby talk. When he gets here this, when he gets here that, we need to do this or that BEFORE hes here.

With all this talk and my upcoming home visit, the talk has turned to a birth plan and who's going to be there with us. There's a couple obvious who's. My darling hubby, my mommy, the midwifes, and our doula.  Maybe my hubby's mom to help with the kids. But I'm uncomfortable with the possibility she'll see the action-and in a full action shot. So we're still discussing that one. And like last time-I've sort of ignored the girls role in the whole thing. Darling E will wonder whats going on but doesn't really understand it. Keke though...this time shes asked if she can be there with us. As this is a home birth really anything goes. If I want her there, everyone will be more than welcoming to have her there with us.

Now I've been a good mommy and shown her a couple birthing videos, she knows where the baby comes out of. Where hes growing. But knowing and witnessing are different things. VASTLY different things. I don't want to traumatize her so badly she'll never have kids of her own. But then again a fully working knowledge of the workings is the best sex-ed there is. Especially with her surrounded by family, and a team of midwives and our doula who shes now known for a couple years.  I want her to believe that the best way to have a baby is with your family, with love and support. Not even in the home, just surrounded by joy and happiness. Even with mommy grunting and groaning in pain. She doesn't want mommy to "have an owie THIS BIG" (that's when she held out her arms as wide as they'd go). And if she doesn't want to stay-because I won't make her. Who's going to take her somewhere else where she'd feel comfortable again? This request brings up a whole new level of logistics.

What should I do? Introduce my ever moldable 5 1/2 year old to how birth REALLY is, or maybe let a slightly flawed sex-ed course cover it vaguely in 3rd or 4th grade while I pretend I know nothing?