'Um, no, I really wanna go to the woods to read my book under peace and quiet, obviously. But thanks.' That's what George should have said. Because it was the truth. Well, that and 'And also you're making me nervous for no reason and that's making me even more nervous and I hate puberty.' That's a tiny bit more like it. But instead what he went for was "Um, s-sure, why not? I-if you'd want me to , I-I'm fine with it." Why? Well, besides plot continuation and his inner obsession with being as polite as possible to people in order to compensate for his inability to properly interact with other human beings, no idea why.