Thank you all for your advice! I will begin smaller and work my way up to something larger.
There's nothing wrong with buying the C25. To help you learn to sail her better, just bum some riding time on a small, fast dinghy or sign up for a dinghy sailing instruction course. There's no need to buy several iterations of boats. It's expensive and not very practical.
There are many small boats to practice on- Lasers, Flying Scots, Hobies.
In a stiffer breeze, the C25 begins to sail a lot like a big dinghy, requiring a constant hand on the tiller and the mainsheet, to play the puffs and avoid being overpowered and dumped on your ear.
I had a Coronado 25 that was like this. It was a good learning platform, and definitely cheaper to operate and maintain than my current 30 footer.