"I got my own passport this year," my guide Wangden tells me, checking my documents. His parents are nomads: he grew up on the Tibetan grasslands with their yaks. "I had to ask my mother when my birthday is so I could fill in the forms."

They don't celebrate birthdays in Tibet, he says, which reminds me that it's my own birthday next week and so I probably won't be celebrating it either.

"So when is it?" I ask.

"She said it's the 15th of March because she remembers a big moon," he shrugs. "But she's just saying that – she doesn't really know."

"But that would mean you're Piscean like me," I say, pleased for some reason, even though I'm actually a typical Aries and I don't believe in any of that shit.

"What does that mean?"

"It means we both like long walks on rainy beaches," I say. "And we cry easily."

"You cry easily?" asks Wangden, surprised.

"God, no," I say, laughing and flicking my hair. "Of course I don't."

That's the great thing about travelling alone: you can invent a whole new personality for yourself and nobody ever needs to know.