I like this guy but my sister is....?

I like this guy a lot but my sister and him are ind of a thing.. will they have kissed and like eachother. But I like him soo much. Whenever I am around him I get that feeling.:) but I am not going to tell anyone really... But I get to see him a lot more than she does too because we go to school together and she is still in grade 8..I am in grade nine he is grade 10. what do I do to either make myself feel better or to make him like me??