What do u do when.........?

u make ure life a mess. U had this handsome well mannered guy who liked u for 4 yrs. He is the best looking guy in this area. Anyway i did not respond to it. After 4yrs of trying he is trying to move on. He is 23 now. I am 25 yrs. Before i thought i was too young. Now i feel i am old enough to have a relationship. Now what should i do to get him back. We have same cles this semester. Help.