I haven't read any of the preceding pages so forgive me if I'm posting stuff you've already seen.

Group rides / races are interesting on Strava, especially if the rider doesn't upload actual power data. I'm one of those - I don't upload power data. Strava guesses all that for me. It's interesting to see what Strava says for me actual vs what it says for me estimated. For example if you look at this race you'll see that Strava says I averaged about 268w for the entire ride. For me I saw 157w avg for the whole ride (tooling around, etc), 202w avg for the race. I honestly don't remember how I did (my notes say I contested the field sprint) but I never broke 900w in the race (877w max). I just remembered - I led out a teammate so I never did an actual sprint - on my powermeter application I have a 45 second effort saved so that was my leadout. He won the sprint (barely he had a hard time holding my wheel), I got second. I think there was a break that won the race.

At any rate you can see that my Strava wattage looks pretty impressive, at least to me, with 268w for the entire ride. The reality was that I averaged 100w under that, or 40% less. Even the race was 65+ watts under that "entire ride number", 30% less than what I saw on my powermeter.

With women's races (only women in the field) the fields tend to be small. That means that minimum power requirements go up. To ride with a group of, say, 6 riders, is much, much, much harder than riding with a group of 60 riders. I'm pretty weak FTP-wise so I tend to get shelled in races where there are 20 riders or less. Even 30 riders is hard because if I make one mistake I can't drift back much to recover. In fact I prefer groups of 60 riders minimum, and 80-100 is more where I feel good because of the massive draft offered by so many riders. Drafting in a big field is like drafting an 18 wheeler instead of a single Ferrari.

What all that means is that if you start racing and you're starting to get the hang of sitting on wheels you can enter a Cat 4 or Cat 5 men's race. The 4s will be a bit closer together, generally speaking. Sitting in, though, I'm guessing that the power requirements will be very similar between the 4s and 5s. By doing this you can do some faster riding that you wouldn't do otherwise. I never average 25 mph for an hour on a solo ride (because I can't, even in a time trial) but in a race 25 mph is kind of average. Things are a bit different at 25 or 30 mph vs 18-22 mph. By riding in faster groups, even if it's not for very long, you get an idea of what's possible, what it's like, etc. Then it becomes less intimidating.