I’m 60 on 29 December. Wooohooo! For the past five years, I’ve already been thinking of myself as 60, and now I’m ready to truly embrace it. Presumably, on 30 December I’ll start thinking of myself as 70.

It’s not that I’m wishing my life away. Far from it. Nor do I want to start acting like a batty eccentric, wearing purple with a red hat that doesn’t go, as in the Jenny Joseph poem. I’ve been happily clashing all my life. Yet there is something liberating about this landmark.

A couple of weeks ago I went to Paris and, for the first time in my life, people stood up to offer me a seat on public transport. Twice. I might well have taken offence in the recent past. Not now, though. If you’re a young ’un and you offer me your seat on the tube or bus, I’ll happily take it. When people remark that my hair is grey and thinning, I’ll say: so it should be. When people laugh at me running, I’ll think: well, at least I’m still mobile.

The thing is, I never expected to get to 60. As a child I had an illness that should have killed me off. And it didn’t. A couple of years ago, I went through a monster depression that I was convinced would see me seeing myself off. And that didn’t, either. I’m still here, singing.

Nor did I expect to hold down a job for 36 years, let alone a job at the same place, let alone one at the Guardian. I’ve met senior editors who have been so disappointed with their life achievements because they expected more. I didn’t.

I grew up in the age of Thatcherism, missed three years of school, and never had a dream. I didn’t set the bar low. I never had a bar. And there’s a beauty to that. Any achievement was a plus. Likewise, I didn’t see myself being an OK dad, or holding down a relationship with somebody I love for so many years. Or still being able to do kick-ups, or learning to skip at 59. If life is a test, having got to 60 I reckon I’ve passed it (admittedly, I am the examining board). And when things go tits up, so be it. I’ve lasted longer and gone further than I expected.

A few years ago, an older friend told me that the 50s is the toughest decade to get through because you’re neither fish nor fowl. You think you’re still a youngster at heart, but others don’t. Nor are you in the oldies club yet. But now I’m getting my 60+ Oyster card, allowing me free(ish) travel on London tubes and buses, there’s no ambiguity about it. Far from denying my age, I’m going to flaunt it and celebrate being a survivor – as we all should.

And I’m relishing what’s ahead. I’m going to visit the numerous countries I’ve not been to, read the big books I’ve not read (yes, that’s you, Marcel Proust), and watch the films I’ve not watched (Akira Kurosawa, here I come).

Best of all, being 60 and embracing my age gives me the licence to be young again. The 30s, 40s and 50s are all about dreary responsibility, caution and not upsetting the apple cart. Being a bloody grownup. Now I’ve hit the big six-oh and am officially an old fart, the pressure’s off. At 60, I have the freedom to be as immature as I want. Game on.