BACKGROUND INVESTIGATION?

I am currently an volunteer firefighter, and want to become a paid firefighter. I have concerns about background investigations. I am 30 years old now, but when I was in college I had particpated in about 5 adult films. I did actually pay taxes on my earnings, however what I did was not illegal. In fact, the Constitution states it is within my first amendment right to do so. Is this something that would disqualify me from becoming a firefighter?

I cant imagine filling out a personal history questionaire that asks, "Have you participated in any pornographic films in the past?" I would not even anticipate this question, but it would most likely come out during backgrounds since I did pay taxes (so there is a legal record). Can my past cause me to not get hired here?

Any thoughts? Any feedback would be appreciated.Thanks!

SM