I would say between the ages of 13 and 18

men are always horny at any age

I was 12 and very horny
I'm 71 and I'm more horny

I am 79 and my wife 76. My wife and I have fucked each day since we got married 53 years ago - barring illness - even all the way through periods - we laid on a towel and wiped ourselves after.
I get greater climaxes now than I did when I was younger.

Tough question. When I discovered my penis at 7 or 8, I could not leave it alone. By 10 or 11, my penis was always hard. By 15 or so, I was hard all the time trying to get someone else to help me cum. About 18 I discovered that my penis was a cock and that sticking it into a woman was absolutely the best thing in life. I spent all of my time trying to get it into a cunt. By early twenties, I was having some success getting my cock sucked or fucked, but it was still my highest priority in life. This was probably my horniest period, and led me to getting married. Probably my worst decision ever. My horny level stayed about the same, but my getting fucked level dropped dramatically.

Horniness stayed high until about 50. My body finally decided that it was not going to get fucked ever again and my masturbation fell off to only every few days.

0-99

any age.

Horniest? Gotta be at around 13 or 14. I don't think it subsided until I was in my late 30s. By that time I would fuck my wife once a week. I found that I enjoyed it more if I let some lust built up for a few days. Now I'm in my 50s and I have local bi/gay guys service my dick. But again I don't really need more than once a week. Although twice is pretty good too. If I did it more often I wouldn't have as good of orgasms.

For me I can say I get hornier every year

I agree with you

From the cradle to the grave!

I'm 51 and am horny constantly, I think more now than ever before and I have been an extremely horny cunt since I started wanking at 7 years old.

I would have to say based on my experience, from age 13- 21

Just before and during puberty was probably my horniest times. Not to say I'm not still horny