In fact, one might argue that you would be doing your students a disservice by not making them aware of your particular perspective. The attitude of the courts generally supports the view that one brings into the classroom one's entire personality, and that in communicating course content to students, a professor will also be communicating other information, including, values, beliefs, prejudices, etc. Many Christian professors go to the other extreme in this regard by unrealistically trying to ensure that none of their beliefs enter the classroom. There are several ways of identifying yourself as a Christian which, if followed with discretion and good judgment, pass the test of appropriateness and, for that matter, legality. The first class meeting is a natural time to communicate to your students that you are a Christian.
Professors often describe their qualifications as part of the course introduction.
Consider adding a few personal touches, such as, I am married, we have a son, and a daughter, and I'm also a Christian. You need to know that sometimes in the course I will be presenting my personal perspective of various issues and my perspective is basically a Christian perspective. Sometimes professors begin a course by having each student introduce himself and share some personal information. I've taught Physics here at the university for 20 years. To help you get to know me, let me tell you the most significant thing about me.