My female was calm like that at that age, up to that age she was quite energetic. To this day she chills out, but is up for anything. She does not need to be doing something all the time. If you'd concerned go to the vet to ease your mind.
Misty- Samoyed Mix, Tannor- Golden Retriever CGC
Robyn- GSD CGC, TC, Midnite-GSD CGC,TC, Brennan-Golden Retriever CGC, Batman-Husky/Greyhound , Apollo-GSD