He's from my neck of the woods, about 2-2.5 hours away. Different district, though. I don't believe that there are any Masters/category restrictions but you will have to verify your Masters results to prove your category finish.
www.road-results.com is your friend.
I would take Caloso's advice and race road in your category and in crits, do both the Cat4 and Masters races. Once you get a base of experience, racing up in ability, which Masters will be, is only good for you.