I need some advice

I write stories basically only for me, but my friend recently found out that I write fiction and she wants to read it. I'm a bit reluctant to show her any of my work off of mibba or elsewhere because all I write is slash fiction (boy x boy) and I haven't exactly told anyone about it. I'm scared of what she may say. I tried to tell her that I didn't want anyone to read it, I said it was 'personal', which is kind of a lie. She keeps on saying that she's my friend and that she doesn't understand why I can't trust her to let her see it.

But she's right on the fact that she doesn't understand. I'm torn with letting her see it - or giving another excuse. What should I do?