If nothing else, think about the message you would send by not submitting for her.
When I applied to go to college, I desperately wanted to attend MIT, and I got in, but I ended up enrolling at UC Berkeley because we couldn't afford the tuition. The next year, my parents very strongly encouraged my brother to apply to Stanford. I felt like they thought that it was more important for their boy to go to a private college, and UCB was good enough for me, since I was only a girl. I understand that that wasn't their real motivation, but it was still a very difficult message for me. (And I did end up transferring to MIT the same year he went to Stanford.)
Please don't make your daughter think that she doesn't need to be a DYS, because she's just a girl.
Also, as a practical matter, I can tell you that it's a pain in the butt to have one child be a DYS and the other not. DS isn't asking too many questions yet about why DD gets to do stuff that he's not invited to, but I can see it coming.
