Lots of really great advice being dished out here! I'll just add my humble experience as a young cruiser to date..
Started off on a cheap
37' with a couple buddies living on and sailed around the NYC
area. Mid twenties. Eventually decided to take a trip down the coast on her and had an absolute blast. Wouldn't change a thing, despite our lack of experience. Learning
curve is fast when you make mistakes
Made it back a year later.
When the time came to buy my own boat, I downsized for something small and quality. I like the 4' draft
and the ease of handling. Easy to sail well. I especially like the fact that I can afford to keep her in very good condition. That said, costs have inevitably been much more than anticipated, even coming from a larger boat and knowing more or less what to expect. Suppose it can be as expensive as you want it to.
Sometimes it'd be nice to have a bigger boat, but it seems like no matter what size boat you have, you're always gonna wish you had an extra foot or two for this or that. I think my purpose-built-for-cruising 27footer is perfect for a young couple and I would only want to get something bigger if and when there are little rugrats scampering about.
My two cents. All the best man