I'm pretty sure that a lot of your negative feelings when you were young come from the stigma associated with people believing that children weren't sexual and your family, parents teaching you that it was a bad thing to show your sexuality at such a young age or that you were some how a bad dirty, nasty little girl if you showed any kind of interest in sex, however they were wrong in that day of age and have done more damage to children psychologically(confusion, guilt, making you feel like a victim, repressed desires, repressed curiosity, etc). So you shouldn't feel bad about what happen between you and your uncle, it was nothing more then normal human sexuality, because studies have shown that children are sexual beings form birth and that they do enjoy and strive to sexually stimulate themselves. With that as fact today I wonder if maybe sub consciously you know deep inside why you did have sex with your uncle....