I'm just curious - have you asked your older dd if she's ever thought about whether or not she might like to skip a grade? You also didn't mention your dd's ages, but I' wondering what their relationship is like when it comes to school and being smart and all that - is there any kind of familial sister acknowledgement that your younger dd is PG or "the smarter" sib or anything like that? Please know, I'm not *encouraging* it, just curious if you see anything like that happening.
I have no idea if you'll be able to successfully advocate for both to skip in your district/school - before you go too far into wondering what to do, you might want to simply check into how possible it is to skip even one PG child. If it looks like you could skip both, I'd consider asking your older dd how she feels about it. We are not in exactly the same situation, but the kids in our family have varying levels of gifted abilities. Each of the kids is very aware of who the EG kiddo, not just in how smart he is at home but in how smart he is at school. A long time ago I worried what would we do if we sent him to a gifted magnet that his sibs couldn't qualify to get into - at the time I saw that as a reason to *not* send him there. In hindsight, I can see that it would have been a-ok - his sibs would have been much more comfy saying he was at that school because he's smart than I was comfortable thinking it would somehow make them feel less smart - they still feel smart and confident in their own personal abilities. Soooo.. that's my long-winded way of explaining, if we were in your family's place (but with kids with my kids' personalities), it would work out ok to skip the younger up into the other child's grade. For other kids, it might be devastatingly difficult. You've got to go with what your own gut feeling is re your children, and if you think they are old enough to have a voice, ask them.
Another option you might consider (if it's a doable option) - have you thought of sending them to different schools? Give them each their own place to shine, and take some of the spotlight off of who's in what grade.
Best wishes,
polarbear
