If your daughter's separation from family, into the confines of her room, were accompanied by changes such as erratic moodiness, chronic anger and withdrawal from friends and activities, I would say that you had some cause for worry. But you state that she remains an engaged student, cheerleader and appears to be a happy child. I think your biggest adjustment to her desire for is your own sense of loss. You enjoyed the feelings of closeness and intimacy that you shared with your daughter - "She always used to be by my side constantly, talking and laughing with me." - and now you miss having her around you, enjoying each other's company on a regular basis. Dealing with these feelings of loss as our children mature and want to spend less time with us is part of parents' normal, healthy adjustments to their children's growing up and moving away. You can and need to stay connected to your daughter by remaining interested in her life and showing her that you still care for her deeply. From what you have said, she seems to be moving through life with a sense of being loved and supported, knowing that you are always there for her.
Teen Pulling Away from Family
Toddler and Teenager Expert Advice from Carleton Kendrick, Ed.M., LCSW