I just need to break out mom!

My oldest went on his first sleep over at a friends house Friday night. He was over the moon excited, and as for me? Well I'm an overly zealous stay at home mom who gets a little freaked out when her kids go anywhere with out her...but I've survived so far. After he left I only called over there twice, even though I thought about it about a million times. I know I'm annoying... My son let me know with out a doubt that he was ready, he needed a break. I asked him a few days prior if he was interested in going over to his friends house and staying the night and boy was he! Trying to tell an almost four year old super excited little man how many more days he has to wait...not fun. We were talking about it and he kept saying "just me mom, not my brothers". So I asked him if he needed a break from his brothers and he said that indeed he did. So we started talking about that and how even mommy needs breaks sometimes, but that when he saw his brothers again he would be so happy to see them and he would realize how much he missed them and such. After I was done babbling he looked at me with this thoughtful expression and said "Yeah, but I just need to break out mom". That was his catch phrase for the next few days. Every time we would talk about the sleep over he would say "I just need to break out!" Pretty cute.
So the big day arrived and he was ready right when he woke up, except he had to wait until the afternoon and I'm pretty sure that was like a life time for him. Then around noon his daddy had to leave so he gave Bubu a kiss and told him to enjoy his sleep over and all of the sudden Bubu looked all unsure of himself, his voice got all wobbly and he asked his daddy if he was going with him (to the sleep over). It total caught me off guard because he had been so excited for days. My hubby told him no and gave me a look. Then Bubu looked at me and asked me if I was going with him and I reminded him it was just him and that he would have lots of fun and changed the subject. He never did cry about it and he seemed to go back to being excited but now I was worried. Was I pushing him into something he wasn't ready for? My husband hadn't been so keen on the idea, and I didn't want to be wrong, but it really did feel like he was ready for a sleep over.
Well it turns out I was right because as soon as they pulled into the driveway and my friend stepped out of her car he was shouting out the window "remember I'm going to your house". Over and over again. He was out of there. He didn't even kiss me goodbye as he ran out the door. He made it all the way to the car before finally hearing the reminder for a kiss from me. Then he ran back, and gave me a kiss while keeping his eyes on the car and his friend. He half heartily hugged his brothers and made another dash for the car. Gone. Not a tear, not a worry, gone. He was ready.
I'm not going to lie to you, I almost cried. Almost. I've tried so hard to raise him with confidence and to see that confidence in action was overwhelming. To see him so grown, ready to leave his mother behind and survive on his own, to feel so self assured. He had never even been over to this friends house before, so it was something extremely brand new for him. I can't wait to pick him up today and hear all about it. To see his excited face. It's funny how as a parent you can feel so proud of all the little things. The firsts.