I just recently took my Black Badge this past month, I am a fairly new shooter, only been shooting for about a year, but I have been a regular attendee to group courses at my local club. The BB course is not a learn to shoot handgun course. You should have the fundamentals down before you attend the course if you want to get the most out of it.
Even if you just take one private lesson from an experienced instructor that shoots competitively, you can learn the proper grip, stance, trigger control, POA, etc., before you attend. This just helps free up time in the BB course for actual shooting skills you will learn for competitive shooting. There is no point in practicing to hit a sheet of paper at 20 yards with the wrong technique, you will just have to re-learn everything again and try to break bad habits.
I can't strive enough, spend a couple hundred bucks on a private lesson and you will save that much in ammo in your first couple months of shooting! BB courses usually run once a month, so why not just take the next one and be the best shooter in the class!