My boyfriend wants me to go snowboarding, BUT...?

BUT... I have a fear of winter sports from back when I was a kid (I'm 22). One time when I was like 11 or 12 I went skiing with a bunch of my family and I had an awful time. I really embarred myself because I got tangled up in the line that you hold onto that takes you up the bunny hill, and I just kept falling down. I was so bad. I remember crying half the time from shame and guilt and being so happy that I had a scarf and hat to hide my eyes. And now, my boyfriend really, really wants me to go snowboarding with him and I just can't get over my fear. I am so afraid of making a fool of myself and not being able to do it, and thus making him He keeps saying that no matter what he will have fun and it's just so hard to articulate the way I feel. I didn't tell him about my traumatic experience. I can't possibly believe that he would have fun doing this with me. Please help me figure this one out...