I feel as though I'm somebody who can appropriately answer this question. I doubt most of you know this, but this summer there was a tournament in Fredericton, New Brunswick (Canada, in case you were thinking near NYC,) that M2K attended. The second I heard he was coming it was somewhat disappointing and exciting at the same time-- as far as Smash goes, he's a celebrity, but at the same time it completely took away any sense of competition. We all already knew who was going to win, and likely who would place, in every game, and it turned out as we expected. The only game he lost in (and I say "lost" in that he lost to SuperBoomFan) was Smash64.
My advice is don't expect to do well. You'll be surprised how many really good players there are. I didn't even get to play m2k in Brawl, which is the only smash game I played competitively prior to Smash4. I only made it to winners semis and lost in the losers there. My point is you likely won't even get to face the people you're afraid of because there are other players who are still really good. It may sound harsh, but don't expect to win. Don't even expect to do well. It's very important that your expectations are realistic, otherwise you'll leave with no intention of going back.