Nice-looking boat and no doubt you could learn to sail on her.
But I too am a believer in 'smaller is better' in boats to learn on. The C25 photos show wheel steering. I think you'd to better starting with tiller steering, the feel is more direct and you never have to guess what your rudder angle is. And the smaller boats have less intertia, are more sensitive to weight placement, and are in general less forgiving while giving you more immediate feedback. This is actually good for climbing the learning curve.
here's an idea, if you have the budget. Do both! buy the 25 and a smaller boat (Laser? Coronado 15?) then you could get the advantages of learning on two different boat designs. Just a thought. Easy for me when I'm spending your money.