Well, I told a teacher who got social services involved, told my parents and they confronted my brother, and my dad said some awful things to me, and the gist of it was that they didn't believe me and they thought that I'd made the whole thing up - although they never said that to me, that is just the assumption I came to. I was never offered counselling. My brother is much more articulate than me and I think he must have told everyone a whole load of crap to convince them it wasn't true. It was sexual abuse, yes. I'm now 30 so it was 20 years ago. In some ways I just think he made a really stupid mistake, and like you say other kids say stuff and talk about it and about practising etc, and I guess they don't realise what an impact that has on the sister psychologically and emotionally. I don't think he has ever or would ever do it to anyone else, but it was easy for him to make that mistake, I'll not let him make another mistake when I have kids.
It's tough that you have never talked to anyone about it, as I said I've spoken to 3 girls in the past about it who have had similar experiences, and that has helped a bit, to at least talk to someone who can understand it. So I hope it has helped you a bit to talk on here about it, thats why I mentioned my experience so that you would know you weren't alone.