I've been leading robotics at our school, Catlin Gabel, for the last six years. What I've found is there's a ideal time to introduce LEGO robotics and FLL, especially for girls 8-12.
Introduce it too early and the kids aren't developmentally ready. You end up doing a lot of the work and the kids don't have all that much fun. They will then think they've "been there and done that" and may not come back to it when they
are ready. Introduce it too late, and the social stuff has already set in and engineering isn't cool anymore.
Every child is different. In my opinion, the ideal time for LEGO robotics for girls is around 5th grade. Some fourth graders might be fine but younger than that you run the risk of peaking too soon. Girls in the 4th-5th grade can do a lot of programming themselves and can reason out the mechanical stuff. By all means get involved with FIRST Lego League...it's a great program. Keep the teams small, though, with younger kids.
It's not too soon for your daughter to get into building things with Lego's, now. Taking things apart is also a nice idea.
Dale Yocum
www.catlin.edu/robotics