As a civilian firefighter, is it acceptable to wear my Class A dress uniform to my daughter's graduation ball at Naval Academy Prep School?

Was your Rate Firefighter? This is the source of confusion.

Mr. Ellington, By all means it is OK to wear your Firefighter Class A Uniform, it is the civilian equivalent of a Military Class A, or Service Dress Uniform. A the Prep School Graduation is a formal event, similar attire as would be worn for formal graduation photo with your family member is appropriate. While Tux or Dress Mess Uniform would be over dressing. Firefighter's Class A can also be considered Business Dress, and appropriate for many similar occasions.

Mr. Ellington-In general, absolutely. It's been some time, but at my graduation from USNA, it was not uncommon for military veteran family members to wear their former service dress uniforms (albeit with strict adherence to standards) even if currently a civilian. I can't see any reason why the dress uniform of a fire-fighter would be any less acceptable.

A few things to bear in mind however...it is very likely you'll "stand out"; military uniforms will be everywhere...less so those of other public servants. I would (as I'm sure you will) ensure I was completely ready to show proper courtesies and protocols as pertains to your department guidance for for colors, etc, and meet the occasional odd questions. Most such uniforms I've seen, whether fire or law enforcement are quite distinctive, and do not look in the least like "military" equivalents...but if yours does...keep that in mind as well in making you decision.

Have a great time and thank you for your daughter's commitment thus far. Here's one old Mid's best wishes for her continued success at Canoe U :)
GO NAVY BEAT ARMY!!