If you can sail a 17-footer, you can sail a 22-footer. The bigger boat will have more weight, interia, and sail area, but you should be able to handle these once you've learned basic sailing and seamanship. You may need a crew or two on the 22-footer, it gets harder to singlehand these things as they, and the sails, get bigger.
But sailing's the same, whether on a small boat or a big one. The forces and momentum are different, but the basic principles are the same.