You see, we keep hitting against this same old thing. Do we want to pass as men at all costs, or do we want to look like what we want to look like? Personally, I would feel trapped if I were obliged to "blend in with the male population" and wear trainers and a t-shirt. I would be pretending to be what I am not, yet again.
So, I think that nostril piercings tend to be worn by women but, if you like the look of it and are prepared for the fallout, go for it! I have one from years back and I have yet to feel the need to get rid of it.
And I have to differ with Shade. Tattoos are just vaguely irritating when they are being done. But piercing a nose? Yaaarrggh! Makes your eyes water.