At What Point Do You Let Go?

This is going to sound sissy probably being written by a man, but I don't care. My son will probably be embarrassed, but again, I don't care.
I just read a post by Mandy that has me thinking about my own children. Her daughter just started kindergarten, and she was torn up about it.
I remember when Nick started kindergarten as if were yesterday. The first mistake Tammie and I made that day, was to let me take him to school. Keep in mind that my kids had and will probably always have me wrapped around their fingers. I took him into the school building and found a teacher to leave him with. I still remember the teacher that took him from me that day, Alice Forrest. I don't know if she remembers it, but I sure do. As she desperately tried to take Nick from me, He was screaming in terror, like if we were sending him away forever. My heart was breaking, but I was holding on tight to a sense of control of my emotions. He had a death grip on my leg as if I was going to have it amputated that day, and he was never going to see it ever again. After what seemed to be hours of horror, Alice and I finally persuaded him to finally stay at the school and let me go.
I got all the way to my car with knots all in my stomach, and decided to turn around and look at the entrance where I took him in......Mistake...... there stood Alice and Nick at the door. I guess Alice told him that she was going to let him wave goodbye to me.
When we made eye contact.....I cried, he cried.....and it seemed like the whole world was in tears...Anyhow....Nick went back home with me and he missed his first day of school. Tammie had to take him to school the next day, otherwise he would have wound up being a drop out from day one. Throughout the course of the school years to follow, Tammie and I noticed a trend. It seemed that everytime that I was in charge of taking Nick to school, there were way too many instances where I would have him skip school just to spend the day with me.

Now, as I fast forward to the present time. The school year just started yesterday, and I find myself still, not wanting to let go. Here he is....16... A junior in High School.......He almost looks like a grown man........I watched him this morning as he was waiting on his bus...He had no idea that I was watching him from the kitchen window....and I felt like crying when he got on his bus....The whole while wondering if my little boy was going to be OK that day.....