I had a 6'5" friend that started racing while weighing around 240. He absolutely crushed flat races by doing crazy breakaways from way far out. By the time he made it to cat 2, he had dropped down into the low-mid 190's.
As a newer racer you should be prepared to get dropped and not be bummed about it. I was dropped and lapped in my first crit, even though I was one of the stronger riders. My tactics just sucked. Most of your cat 5 races will be you learning the game and how to read/ride in the pack.