I think that going from a max of 25 miles to riding 100 miles in just six weeks is too fast. That doesn't mean you won't be able to ride the 100 miles - but ride it well?

I did a century with a friend many years ago. I trained for the century, getting a lot of miles under my wheels and working up to longer rides on a consistent basis. My friend - who was in very good shape - did not do the distance training. She rode shorter distances consistently, and she did some shorter distance triathlons. She had a really hard time finishing the century (and it was a ride, definitely not a race). In contrast, the distance was much easier for me, and I could have happily continued riding at the end of the 100 miles.

Does this ride have a metric century? I think that's still a big jump in miles, but it feels more possible to me. And you can still say you're planning to do a century (100 kilometers is certainly a form of a century).

--- Denise