I can imagine the thoughts going through your son's head as he tries on his clothes. He wants his privacy. He's interested in your reaction...probably much more than he lets you know. But more than that he is thinking about how his peers will see his new clothes. 11. He is so acutely aware now of what others think of him. A wonderful, and challenging time.
Your patience is perfect. You step aside and let him do what he feels he must. Just a little bit now. It begins with clothes and then more distressful (for you) signs of independence. You will probably suffer 😄 through all of it, as you rejoice in his growth.
I raised two children and helped to raise a grandchild. I taught adolescents. Such a hard time, and yet such an exciting time for you as parents, and for him.
I wish you good luck, and much happiness in this amazing process of helping your dear son to grow.