To steal a phrase, just do it. Only I would add-HAVE FUN!

i'M 37 and was once a competitive sponsored cyclist approx. 15 years ago. I started riding again about 4 months ago and am now focusing on triathlons, but will be racing the bike as often as possible as well. Don't even worry about being "fast enough." Think about why you are doing it and set some goals to keep you motivated. Here's a push in the right direction. Racing is one of the most thrilling things you can do on a bike and the culmination of all your training. It gives meaning to all those speed drills, long rides, and eating right (and buying all those toys that go with racing!). It sounds as though you have more than enough base under your belt and should do fine. You don't have to beat anyone or make Cat. 2 your goal. Concentrate on staying healthy and uninjured. With that you will become consistent, and your age group will start remembering you as "that guy who's always in there with us" or "took his pulls." There's nothing more exciting than closing in on your age group or keeping up with a younger group for a while. If it helps, find a group of like-minded riders bent on pushing the boundaries of our age group.

As a side benefit the gut will start shrinking and the significant other will notice. Now that's a goal!

At any rate, my hat's off to you and I'm right there with ya. There are also many physiological reasons why one can be compettitive in cycling well into "older" age, but I won't bore you with them.

Race on!