Ok so I like this guy, but he thinks that I am too young.. when he is only about one year older than me.. So how can I get him to like me?

There is no guaranteed way to make someone else feel the same way about us as we do them. Its all part of the game of Love. The most we can do is plant a seed and pray it takes hold and with some TLC, it will grow in a good relationship but chances are more than not, nothing will happen so the more seeds we plant the better our chances are that one will take hold. Now a little secret that wil work at any age and any sex is to do your homework and find out his likes and dislikes and then find some you two have in common and work on those with him and don't tell him you like him.  He will figure that out for himself sooner or later until the appropriate time. So be yourself, don't hurry anything and remember life comes with no guarantees.  Good luck