[Nyororin]

I think it`s really going to depend more upon your surroundings than anything else. In some circles no one would even notice, yet in others it would be totally unacceptable.
Universities are generally quite lax - they don`t have uniforms or dress codes. I doubt that they`ll tell you not to wear them. However, there is a fair chance that they wouldn`t give a good impression to a lot of people.
You may see a lot of young people with piercings, but you pretty much never see serious adults with them. I think there is a lot stigma attached, and chances are you will be looked at as not being a serious student.
It`s not that they`re rare, but rather the crowd with piercings usually isn`t the type of crowd you`d want to be associated with.

I mean, even for girls, clip-on earrings are still more popular than actual ear piercings.