I don't like these categories- almost all boats are more than 20 years old, the question is how much older? Boats easily last over 100 years if well maintained, and they've been making boats for almost as long as people have been on earth! Having 20 years as the maximum category is crazy.
My boat is a 1974 (35 years old) Catalina 22. My dads boat is almost 80 years old!