I am building a bonus room over my garage... above the room is attic space with no current insulation. I have already installed a 6 mil vapor barrier to the joists and then put up the tongue and groove beadboard ceiling. I plan on blowing in R49 fiberglass insulation in the attic. I'm in Nashville, TN.

Will this be adequate to prevent mold and moisture issues in the attic? What about efficiency?

I did not want to put drywall between the joists and the ceiling panels since the overall ceiling is rather low and every 3/4" matters significantly.

Please let me know of any concerns... I would hate to have to tear the ceiling down after spending so much time and money on it, but I don't want moisture or mold problems either.