Jane Merrick: It should have been me wearing Paula's GB vest

Twenty-two years ago, in a soggy field in the Midlands, a skinny, blonde 12-year-old by the name of Paula Radcliffe came 299th in a cross-country race.

About 200 places ahead of her, there was another skinny, blonde 12-year-old, trying to shield her face from the flying mud and grass – and that girl was me.

So Paula, you won't remember me from that day – 15 February 1986 – just as I don't remember you. I can barely recall the event itself: all cross-country races run together in my memory. But, piecing together the evidence of our life histories, I can say that I once beat you, one of the greatest British athletes of all time.

Born 24 days apart, in 1973, we were both fairly average runners at the age of 12: neither of us had a prodigious talent. But since then our lives have taken us in different directions: you became a marathon world record-holder; I gave up athletics at 15 when I discovered boys, cigarettes, alcohol and, a year or two later, journalism.

I've often wondered what would have happened if I'd had the willpower, the determination, to train as hard as you. Would I be with you in Beijing?

By the late 1980s, I had an ambition to make it to the 1992 Olympics in Barcelona, and win gold at the 1,500m, my favourite event. But someone – at school, or at Liverpool Harriers – made it clear if I ever did get there I'd struggle home in eighth, at best.

And so my athletics career was over before it started. By the time we were 15, I ran my last cross-country race somewhere in County Durham. I came 256th. You were probably in the top 10 by then. Shortly afterwards, in the park opposite my school, I had my first cigarette.

You've probably never smoked a cigarette in your life. It was wonderful. At 16 came a vodka and orange, or two, in Kascades bar in Mossley Hill. And then I started kissing boys. There was no going back to 7am training runs after that.

By the time the 1992 Olympics came around, when we were 18, I watched the women's 1,500m race aghast as the competitor from Western Samoa came last in a slower time than my personal best of just over five minutes. "It could have been me!" I shouted at the TV. "Only if you'd emigrated," observed my Dad, helpfully.

When you were in your first Olympic final, the 5,000m, in Atlanta 1996, I was skipping lectures and drinking in the Leeds University Union bar. When you broke the marathon world record in Chicago in October 2002, I was hunting stories of plots to unseat Iain Duncan Smith at the Tory Party conference in Bournemouth.

By April this year, the cigarettes were long gone and I'd managed to stop drinking for enough weeks to train for the London Marathon – my first.

I was looking forward to Radcliffe vs Merrick: The Rematch. Twenty-two years on from that muddy day in the Midlands, we would be at the start line again – 26.2 miles ahead of us, half a lifetime behind us.

But Paula, where were you? I couldn't believe you'd pulled out because of a "minor" toe injury. I pulled my calf muscle training in Dulwich Park, but bravely fought through the pain to turn up on race day, and finished in 4 hours, 49 minutes and 5 seconds – 5,980th, if you must ask.

Every four years, when the Olympic torch is lit, I feel the frisson of excitement combined with the jarring pangs of "What if?" But for the rest of the time, I don't regret one single kiss, cigarette, or vodka and orange.