Hey Surrender.....sorry you're feeling down today. When I turned 50 I was severely depressed about it. Now I'm 52 and I still feel young (most of the time)....I know what you mean though....I look at my nephews and think....wait a damn minute. You were just a toddler and now you're a grown man! WTF happened?!! Time seems to go by exponentially faster as I get older.
Happy birthday to your son
And you're as young as you feel (At least I keep telling myself that)