I don't want this to be true, and I must admit it seems a bit unlikely. For most of the 60s Dylan could have had pretty much any woman he wanted, if he'd had a thing for young girls extending to illegally young girls then I'd have thought that there would be a history of very young partners just over the age of consent. There isn't, so if the alleged incident happened then it appears to be isolated to one person. This seems unlikely, Dylan's (widely reported) choice of women at that time was women around his own age. He doesn't even seem to have put it about that much. Most young men in that position would, we all know.