When you say, "put her back on my health care" I assume she's not on your healthcare plan now. You may run into difficulties putting her back onto your coverage unless she's had a qualifying event (lost her job with her own coverage, exhausted her COBRA, etc.). Why is she not on your insurance now?
The change to the dependent child coverage occurred in Sep 2010. There was a 30-day transition period that allowed parents to enroll their dependent children up to age 26. I'm not sure you can just add her now unless there's a qualifying event.