I have been reading the book "Bike for Life." Last night I read about a guy who had trouble keeping up on rides with a friend. Then he got a professional bike fitting session and a new bike to match. Now he is faster and no longer hurts after a ride. You can probably read about bike fit and tweak your own fit over time and distance to get pretty close to what you need, but allow yourself hundreds of miles to arrive at a pretty good fit for you.

You are young and think you will be faster when you are older. I am older and think I would be faster if I were younger. Attempts to be fast usually drain me and I cannot ride for a few days. I do what I can, but always try to make certain I am enjoying my ride. After a while, you notice you are stronger and faster.

Take plenty of time to rest and recover, too.