No you should not be visiting the mikvah. Mikvahs are specifically built for the Jewish community (exception being those who wish to join via conversion are required as part of that process). Whilee the idea of mikvah be seem nice it is important that G-d has a designed path for each of use to follow. I would suggest you take a look at this website which talks about the 7 laws given to Noah and his descendants... http://www.noahidenations.com/ also this article... http://www.chabad.org/kabbalah/article_cdo/aid/380332/jewish/The-Mitzvot-of-Non-Jews.htm