So you are 37 years old? You are plenty young enough to ride a road bike at 20 mph, if you get into condition.

It is hard to say whether you will do better on a road bike then on a hybrid. I have seen some people upgrade and not see much if any improvement. I have also seen people upgrade and see dramatic improvements.

When I switched from a touring bike to a racing bike, I saw an improvement. Once I got up to speed on the touring bike, it was fine. But the racing bike handled better and I was able to take corners faster and accelerate faster. So it was far easier to get up to a higher speed so I did it far more often and that resulted in higher average speeds. Also since it was easier to accelerate, I was more willing to do it so there was an emotional component also.