Hey there...

Categories indicate your level of experience and/or performance. For the east coast of the states (I'm not sure where you are) the starting Category for women is Cat 4. (I think the west coast has Cat 5?) As you race, you accumulate points (USA Cycling has a system for points awarded for place, etc.) and you can upgrade to a higher category ( 3, 2 and 1 is the highest) based on the collection of those points.

If you go to the USA Cycling website, there is a lot of information regarding races (assuming you are in the US of A!)!

Good luck...ask more questions here if you have them...the TE ladies are ALWAYS full of useful info and hints!