Im sure age has something to do with it - but i kept training diaries which outlined all the information about my training and racing - and the average speeds were only just above the first C grade ride i had earlier this year.
I have noticed that C grade seems to do similar average speeds to B, but B is harder as C tends to have less attacks and can keep a higher average as a result, B also can do similar average speeds to A but the attacks in B tend to be slower and shorter.
Lots of the time A can be going not that much over 30 km/h with riders all looking at each other then bam a big long attack at 50 + km/h followed by a counter attack, then another look at one another before another attack is launched.
As always, 100% correct. You could be The Ferret, but with manners.