Magdalen College Cloisters We're no longer in between seasons. The weather has become fiercely autumnal, and from my study window I can watch the steady fall of leaves and feel simultaneously nostalgic for summer, when we sat outside eating roast chicken and salad, taking our jumpers off to reveal almost-brown shoulders, and happy to be here where the air is fresh and the pubs smell of wood fires.

I've taken up swimming. I use the university pool because it's so close to my house; I also like the feeling it gives me, like I'm an outsider who's made it inside, a spy, a double agent. I don't know what I look like to them - not obviously old enough to be out of education, not obviously young enough to be a bright-eyed, messy-haired fresher, either. One of my greatest conceits is that I imagine everyone is always looking at me all the time and trying to figure me out. I only think this because it is what I do to people. I'm dangerous to have around; I am constantly making up stories.

On a weekday evening I emerge from the pool and shower in the changing room, next to a small woman with pert breasts. I have never mastered the art of the changing room; I look around too much, my hair drips, I don't know how to change subtly behind a towel, I don't know anybody so I can't have a casual chat as I get dressed again.

Tonight a gaggle of students have gathered and are preparing for a nighttime workout; perhaps they're members of the swim team, for they speak in phrases like "stepping onto poolside", which makes it sound like they Know What They're Talking About.

They're recovering from a big night out. One of them, husky-voiced, tiny and blonde, is reliving her drunken antics; another of them, also tiny and blonde, has slept with a man called Joe.

"I thought everybody knew," she says, when the husky-voiced girl expresses her surprise. "But as they don't, can we just keep it between us?"

And then she says, "did you get with anybody?" and looks a bit crestfallen when the husky-voiced girl says no. Perhaps she wanted a comrade-in-arms. Sometimes long late nights with lots of friends can make you feel lonelier than ever, and she gives off an air of being isolated. Her action has given her something to hide; everybody else is open, unfettered.

One of their friends comes back into the room. "Getting all the gossip?" she says.

"Yeah, I am getting all the gossip," the husky-voiced girl says, but she doesn't mention Joe. A closely guarded secret is born.

This is probably how female friendships are broken, I think, but I don't know for sure.

When I leave, a tall boy holds the door for me. Perhaps he thinks he might later run into me, at a party, at his college. It's the start of term. People think lots of funny things at the start of term, myself included, although I'm not a student any longer, and I haven't been for some time.

More likely he doesn't think of me at all. I get on my bicycle, disobeying the signs that tell cyclists to dismount on the narrow path, because I've noticed that everyone disobeys, and I think it must be an unwritten rule. At home the Man has made a butternut squash risotto and turned the heating on. I have that happy sleepy feeling that comes after a swim and we drink the rest of the white wine with our dinner and go to bed early.