I present as male, yet have very long hair.
I've wanted long hair all my life, but finally decided to grow it about 10 years ago. My stylist was very supportive. I got a trim (~1/8 inch) about every 3 months to keep it looking good. Once it was long enough, I wore it tied back. That awkward, in-between stage is something that everyone goes through. It takes determination!
It took me 3.5 years to grow my hair to my waist. I now wear it 2-3 inches above my waist.
I did not begin growing it until I was well established in my profession, so I never had to interview with it long. But no one at work ever said anything to me.
There are plenty of professional males today with long hair. Take care of it and keep it looking nice & healthy!