First of, you couldn’t be possibly responsible for that. Even partially. Because you were too young for having any say in that matter. This is why they have such a thing as the age of consent – the age from which you are old enough to make conscious decisions. And this happened way before you reached that age. So don’t be even thinking you were ‘offering yourself’ – a six year old offering herself, just saying this sounds ridiculous, this is nonsense, you didn’t know what you were getting into and you couldn’t know if you want it or not, your child curiosity was taken advantage of.
Second, a boy of 14 should have understood that you are too young for this, he wasn’t a little kid anymore who doesn’t understand what he’s doing. Sure, teenage hormones and yadda yadda yadda, but the ability to think with our brain and not with our glands is what makes us humans. He didn’t care, he went along with it anyway. And the fact that he threatened you means he felt scared – he knew he’s done something wrong.
I don’t think he blocked this experience from his head, emotional moments like this are not easily forgotten. I think, or at least I hope he feels bad for what he’s done. I think you should talk about it to him. Maybe you will find a way to forgive him or at least get some sort of closure on that.