Feeling kinda old lately

Not sure what brought it on, normally a person has these moments at times when they turn 30, 35, 40, 50 etc but I feel it's recently happened to me. Not sure why, birthday number 37 doesn't
t happen for a few months and I have to very young daughters who help me feel young, so not sure why it is. Maybe it was realizing that some guys I play ball at the Y with are like 15 years younger than me, and I am inching closer to 40, maybe it's the physical fitness test for work and realizing my best years are behind me, or maybe it's just the fact I keep getting more and more gray hair. It's not like I am going completely gray now, but I seem to notice it more when there is no gel in my hair. Grey isn't really that big of a deal, at least I still have my hair, but gray hair tends to be more course and stick up and just generally not look as nice on me. Maybe I should bleach my hair and cut it to hide them or maybe color my hair darker. Of course the same would have to go for my facial hair. Ahhh what is a guy supposed to do!? I still act like a guy in my 20's, I need to take better care of myself to feel that way, more exercise for my knees and other ailing joints, and I must do something with my hair. Well whatever I am sure I will adjust how I feel in a while and it will pass, but it'll come back later. Gosh what am I gonna feel like when I turn 40?!?