It's strange how life hands you chances to do things you never thought you'd do again, but there I was on Saturday, on the lower end of an 8ft helium balloon, marching through Manchester to protest about the state of the NHS. Before then, my previous protesting experience, as a punter rather than an observer, came back in the 1990s, before my young mind had even had the chance to be disappointed by New Labour, protesting Michael Howard's Criminal Justice Bill.

Back then, as a callow, long-haired teenager in that awkward space between A-levels and a City and Guilds, protesting seemed like the most natural thing in the world to do. The Government were taking away our Right to Rave, and we were Angry. Angry with a Capital A. We yelled, we chanted, we threw stuff (actually, I didn't; I left Hyde Park "before it all kicked off" to get home early for my dinner, but you know what I mean). We blew whistles. We read the Socialist Worker. We screamed and we bawled. We were young, and we thought it all meant something. Hell, maybe it did.

When you're a teenager you're pretty angry about everything. Politics is just one of the many thousands of things that seem utterly and irrevocably unfair; you gravitate towards it because you might as well find one more thing to complain about. Teenagers are built to rebel against nothing they can define because they simply must; at least, with political activism, it makes more sense, or seemed to at the time.

It might sound like I'm about to dismiss campaigning and protesting as something somehow callow or a phase you have to go through, but I'm not. In fact, I'm beginning to think quite the opposite. The teenagers are right to be angry. I don't know if they know they're right, or if they're just angry and happen to have stumbled on the right mood for our times, but I am more and more convinced of the righteousness of their cause.

The older I get, the more it's beginning to make sense again - the grumpiness, the anger, the disobedience. Maybe now is the time to get back involved, in a kind of middle-aged activism, the kind of anger that comes from knowing just what a miserable, lying professional foul the world is, and how much better it could be.

So there we were, marching through Manchester, a ragtag-and-bobtail collective of trade unionists, activists, protesters and - it irks to say this, but I'm very much afraid it is true - the Usual Suspects. Yes, SW were there. Yes, I got offered a paper. Yes, someone handed me a leaflet about The Death of Trotsky. Yes, there were calls for a General Strike, which will garner the well-meaning movement about as much public sympathy as a slap in the face. Yes yes yes, all of that, but wait: it's easy to dismiss this kind of stuff by looking at the clichés and thinking it represents a simplistic identikit of the aims and objectives of those who dare question the happy neoliberal consensus of austerity first, everything else later. But what if they're right? What if it is worth stopping the NHS from slipping into the meat-grinder? What if there is a better way than cutting everything, privatising everything and outsourcing everything?

It wasn't just us making a noise (thank you, PCS samba band) that chilly Saturday: there were others taking to the streets, for UKUncut to protest Starbucks' buffet tax options, against the Scientology shop in town, and so on. A lot of people are angry. A lot more, you might argue, ignored all the fuss, the noise, the banners and balloons; they carried on sipping their dishwater lattes and filling their heaving plastic bags with Christmas shopping gifts now, playing chicken with the overdraft limit later.

True enough, I suppose. There is apathy everywhere, and maybe only pockets of activism to try and stir the bewildered Christmas shoppers from their numb slumber of melting plastic and payday loan sharks. I don't know if the tide is turning, or if anything will change anytime soon due to getting out on the streets and making a noise about it.

But. oh, I don't know. When we come to look back on this time, when everything relatively decent that we managed to get from the postwar settlement was dismantled and chucked away, do I want to think I didn't do anything about it? Or can I, at least, say that I did something, that I stood up and I said, enough is enough?

Even if it is just a feeble attempt to save what can't be saved, I think you have to try. Probably the teenage me, who took part in that other protest all those decades ago, wouldn't understand, but I do: you have to try. Not because you think you'll win, but because you simply have to try. Because if you don't, the only person you can blame for the way your world turned out is yourself.

Get marching.