I only have a 23 month old, so take anything I say with a grain of salt...
To me, it's a no brainer. I'd pull her out. Try again at a later date when she's more mature. If one of you really can't take time off from work, then I like the nanny idea. I realize you're a teacher and probably believe in the system, but I've planned to homeschool since birth and I've had some great experiences with all the homeschooled gifted kids I've met. They seem pretty happy and well-adjusted and when they're together, they just get along so well.
