Hi Brittany,
I think your children sound like they would be in good company around here.
If you think DD might like a pre-school, keep looking around. I found a 3 year pre-school that would take DD8 at 2yr.5mo., but she was also already potty trained.
If your child is advanced past pre-k academically, there isn't any harm in putting her in pre-k for social reasons, especially if she likes it.
Just don't pay the whole year tuition upfront!
IMHO I'd wait til the child is 5 to test. I believe that's the earliest to test for an accurate eval, give or take a month or two.
Welcome aboard.
