Listen to Stillgoing
Lot's of good advice here....BUT, stop worrying about your bodyfat percentage. The mirror is your guide. (If there is anyone under 10% bf at the Novice level it would be an exception) Most people, I believe, even with devices are way off on their bf %.
Just go to a show and watch. Enter one, that's the best way to learn. Your real goal is to be your best. I've done 9 shows over the years for the same reason you're thinking. A goal to inspire training, diet, appearance and health. I've done everything right and wrong through trial and error. At one show the competition sucks, at the same show next year, I thought I had gone to State level by mistake because the comp was so good.
You don't say how tall you are but StillGoing's giude is good for approximate bodyweights. In your picture, you look okay at the Novice level, go for it...
By the way, at any show I've been in, the top couple of placings were always juiced, maybe not significantly, but enough to see the difference in the classes. If it ever came down to size or conditioning, being is shape seems to get the edge.
Good Luck, working hard and then comparing the results against peers for an audience is exhilarating!!! You'll love it!!