Questions before first race.

Hey All,

I've been road biking seriously for about 4 years now (22 years old) and looking to do some races. I know people say its not just about speed but what speeds can I be expecting for a cat 5? I have a ton of experience riding in a pack and really want to keep pushing myseld. I ride mainly alone but when I ride with a small group I am normally quite a bit faster than them. So it's tough to be pushed past how far I push myself.

Thanks for any help and advise!