Believe me, you will be fine. I bought a bike at age 57 after not biking for years, and now I easily do 40 miles alone. It's great that you are getting some instruction and generally going about this right.

You will find great support for bikers at every level here -- there is no snobbery that I've seen, and the most basic questions will be answered by knowledgeable people. Also, if you are scared or frustrated there will likely be understanding and support.

Good luck and keep us posted on your progress.