My step cousin has a crush on me. what do i do?

My step grandfather, who is like my real grandfather has a grandson who is 4 years older than me. Ever since Christmas he has been trying to convince me we should hang out and stuff. He is very sweet, but I don't like him in that way. I just can't get over the fact we are like cousins... We didn't grow up together because he lives about 4 hours away, but still we see each other once a year at family gatherings and it's going to be awkward.... Please help, I don't know what to do. :(