You don't usually have weight divisions in smaller tournaments. In fact, i've only ever been in one tournament that had weight divisions.. and that was a state tournament. Even then, there was nobody in my division so they had to bump me up to the next one. Just gotta suck it up and bare it, lol.
I know what it's like learning a form right before a tournament. lol. I had to do that once. The conversation about a week before the tournament went something like this
Instructor: You going to the tournament?
Me: I don't think so, I don't even know my form yet
Instructor: You can learn your form, I'll help you.
Me: In one week, I'm not sure I can do it.
Instructor: You're going.
Me: Yes, sir...
lol... I won too. However, at the time the form I learned was much less advanced than the one you performed. You did an excellent job for learning it so shortly before your demonstration.