It turns out I am actually Cat 3 in Cross, probably because I'm Cat 1 in MTB. They let me race Cat 4 since it was my first serious CX race. I've done a few on my mountain bike but more for fun/the challenge than anything. Cross is huge in the Midwest and probably huger with my teammates.
Cross is a lot of fun, it's defiantly the most family/friend centric type of race. Everyone had their wives/husbands and kids there to cheer them on. Mountain bike races generally are the same but you only see the racers once a lap, and there aren't breaks between categories.
I placed 23rd out of the cat4/juniors so not bad.
Hopefully I won't be stomped on at my first cat 3.