I rode it when I was probably 16, on a mountain bike. I guess I don't remember it being that hard. It's been a while, though.
The website says 2675 feet of climbing. I've done that on dirt on my 35lb mountain bike, in an hour.
Yeah, it's going to be hard on a fixed gear, but I probably won't have a geared road bike by then, so I might as well stand up and suffer.