All wrong

Marvin felt woozy for a minute, and everything suddenly went dark. He felt strange as he fumbled around for a light switch. When he turned it on and looked in the mirror, he got the shock of his life. He was in a woman's body, but it wasn't just that--he had to be at least twenty of thirty years older. He could tell from the looks of her that she was struggling to maintain her youth, despite being at LEAST in her 50s. What he didn't know was how it all happened. She was an older woman looking for a youthful body, and she found herself a spell on the internet to swap with a younger woman that would have accomplished exactly that. However, a slight mess up on her part caused her to switch bodies with Marvin. She cursed the fact that she got it all wrong, and that she was now a man.