Ratings and Comparable Skill Level

I am about to enter my first chess tournament in the U900 section, and I am curious to know what the skill level of my competition will be.  I looked at the pre-registrants, and most of them have a rating from 500-900.  Can somebody please explain how competent these other beginners are?  At about which rating do players stop making moves like forgetting that their queen is attacked and the like?

I don't make blunders, but my tactics are very poor.  The only way I really win is by capitalizing on my opponents' blunders.  I'm just trying to gauge how I'll fare in this tourney!  Thanks to all who respond.

Edit: Also, how comparable are chess.com ratings to USCF ratings?

1326 turn based should equal something like 1000-1100 USCF

You can probably win a U900 section.

Yes I can see that after 30 standard live chess games your rating is 1069. That should be close to your USCF rating.

Thanks!  Good to know.