Ok, in which case pick one that you feel comfortable with, and let them know you expect to be able to talk "in confidence". They already probably do that, it's like doctor-patient privilege, they won't say anything to anybody else without your ok.
Your student handbook might have some info in it, too.
Also, perhaps your school has a LGBT (Lesbian-Gay-Bi-Transgender) support group? I would be cautious about seeing anyone other than a counselor, though...the more people who know, the more likely your trans-status might get out. If you're comfortable with that, no prob...but if you're not, a little discretion goes a long way.