R.C.
First, congratulations. In this day, asleep by 8 is considered very good.
But one of the best things about children is that their behavior is a wonderful guide to individual needs. Yes, it is very possible that she needs more sleep. My daughter had to be bathed, read to, kissed and left to sleep by 7 every night, 7 nights a week. She is now an adult, and still requires a full nights sleep. By meeting her needs, she was a much more pleasant child and is a very successful, well-rested adult.