I don't have any laboratory numbers, but I can offer some experience of what it's like to get into racing at your age - I was 57.

I was, I thought, very fit. I didn't (and still don't) know my VO2 max but I'd been spending a lot of time on the bike for about seven years and I knew I was as strong as a lot of my riding companions who raced - some of them much younger than me. So one day, encouraged by a friend who is a coach, I took out a licence and pinned on a number.

I'd been around races and bike racers a long time, but the intensity of that first experience took me by surprise. I found that, fit as I was, I couldn't hack it in a race. My immense base equipped me to hold a high, steady pace (if I could swim any better than a housebrick I'd make a great triathlete) but the race seemed to consist of nothing but a series of intense sprints separated by very brief rest periods. They spat me out the back in fairly short order and once gone, there was no coming back.

So, I started training for racing. Intervals, tempo rides, more intervals. And I sharpened up my bike-handling skills. I hadn't been accustomed to making physical contact with other riders, and I suspect that takes a bit more getting used to when one starts so late. And before the end of the season I was hanging with the lead group in the non age-related Cat4 fields, though not winning anything - like IBOHUNT, sprinting is not my strength.

Which is a long-winded way of echoing the fact that a high VO2 max is a terrific thing to have in terms of potential, but being race-fit, in every sense of the word, is a different matter.

And I'd strongly support what shovel said about thinking about what drives you, what you'd like to achieve. Racing is hard and dangerous and intensely stimulating, lots of people find it addictive. I'm not really one of them. I started racing mostly out of curiosity about where I stood, fitness-wise, not out of any real urge to win. And once I had a measure of that and knew what it took to be competitive, and how to train with that in mind, I found I could take it or leave it as far as the actual racing was concerned. In a sense I didn't train to race, I raced to give myself a reason to train. So when in my third season my "career" was interrupted by injury, I wasn't motivated to get back to it. I still do most of the workouts I was doing for race training, though, and I'm extremely glad to have had the experience. I'd certainly encourage you to give it a try. The guys and gals in this forum are an unfailing source of information and encouragement, if you decide to do so.

One more thing. There are some freakishly fast old guys out there.