My Kalina is the same age. She goes to bed at 10PM and sleeps soundly until 6AM. She goes outside and does her thing and then she goes back to sleep until 8:30AM at which time she eats breakfast. She plays and naps throughout the day, off and on. I let her sleep whenever she's tired because it's good for them to sleep. She's energetic and crazy when she's awake. I think your puppy sounds perfectly normal. Oh, and some days she is definately more sleepy than others.
