Kellie, it sounds like her sleep pattern is changing. I would try and keep her up in the morning as you suggested and if need be put her to bed at night a little bit earlier.

If she gets grumpy in the afternoon get her to have a rest on the couch with a couple of toys or a few books. Quiet often she will fall asleep, wake her up after a short time by making a lot of noise.

It's just one of many routines that will change over the years.