Just about anyone can get to 25 mph with lots of training (mostly lots of miles). I built up for a week tour of 600 miles. When I finished I could hang with anyone/any group. I did interval workouts with a group that hit 35 mph in the paceline after that week.

So it's really whether you have the time and motivation to put in the big mileage base and a little speedwork. It takes a lot of effort and devotion to go from 80-100 mile weeks to 300+ miles. But if you decide to do it, 25 mph isn't unreachable. 30 mph is for a small group of elite pros and 50% of the BF posters.