Is he interested enough in me?? Help!?

This guy, John, with whom I was in a musical with, is my age (15 and a sopre). We barely talked, but sometimes he would be talking in a group where I am, then I would smile and look at him and he would stare into my eyes for 5-6 seconds and not look away until I do. Once we were sitting across but not close to each other, and I noticed him looking at me from the corner of his eye, then when I looked back he put his hand out and motioned me to come over to him, and when I blushed and smiled, he smiled back very sweetly before he had to leave. And finally once in "circle time", where everyone who performs stands in a circle, crosses arms, and hold hands with the person on either side of him, he walked up to stand next to me and when I held his hand he squeezed it a few times. One time when everyone let go to clap, I didn't get the chance to, and he also kept holding on to my hand. I want to ask him to go with me to sadies. Is it worth it?