My grandfather is the manliest man I know, and not once, in my whole entire life, have I seen him cut his hair. Look, if you can take care of it and rock it, then honestly who cares? As a female, I have shorter hair, but that's because my hair tends to become very oily without a shower EVERYDAY. I have tried everything and it doesn't work. I was never a fan of my once long hair and so in high school I cut it off and never looked back. My grandmother almost cried but she came to terms to it eventually. It made me feel better and she understood.
So if longer hair is your thing, ignore the naysayers and rock that hair you were born with hun!