I'm pretty surprised the principal would think discussing himself in that manner, one way or another, would be appropriate. That's nobody's business.
School faculty, to my knowledge, is generally encouraged to remain neutral on such topics, supporting students personally, as human beings, without injecting their personal beliefs and experiences into issues that could garner too much attention for the district should someone get upset. Teachers tend to become very efficient at showing their student/s they care and support them without any political/religious affiliations being endorsed. (which is a good thing for a state run school, as the foundation is the government and not Christianity)