For novices - every race is an "A" race
I had an interesting discussion with an athlete recently about A, B and C races. I think for novices every race is an A race. I say that because each one offers significant opportunities for learning, development and improvement. You should go out with a competitive mentality each time, with a specific race plan based on your training history. You can only expect to go as fast in a race as you do on a good training day. Once you have about half a dozen races under your belt and a season history of competition, then maybe its time to start focusing on A and B events.