Aging sucks

I hate aging, and I am only a 39 year old man!
I have gray hairs appearing everywhere on my head now, which I try to pluck or dye. A couple of my moles are getting larger (I checked them out; they are benign, but the doctor laughed and said "you're not 18 anymore".
My butt is getting less firm and I am putting on weight easier on my abdomen - which means I am more self-conscious in a swimsuit. My joints ache sometimes. I have problems digesting certain foods now, like milk. I feel like I am beginning to lose my looks.
I can't identify with 18 year olds like I used to, or party until dawn three days a week.
My orgasms are less pleasurable than they were when I was 20, and I can't shoot my load as far anymore. I find certain 50 year old women hot, and most 20 year old women seem too young. I want kids, but I feel like I'm getting too old to start a family.
I feel my time is running out to make my mark in the world, but I also worry that no one will remember I was ever alive when I pass on. I no longer feel like I will live forever, but I don't want to live forever either.
I feel that life is more precious now that my life is half over. I wonder about the reason I am still alive and so many of my friends and loved ones are no longer here.
I want to move and start a new life, but I'm scared of change.
Worst of all, I feel the need to complain about getting older on websites like this one! Is this normal?