@Zoom-Zoom, good points. I have practiced yoga for 2+ years so my flexibility related to cycling is very good. On my hybrid, which I have had for 6 months, the only little "twinges" I feel after long rides is my upper back near my neck. I think it's because of the angle of my body/neck. I do realize that it will take time and regular riding to get my body accustomed to new cycling positions.
Interestingly, my legs & glutes are never sore, even after my longest rides. I suspect it's all the running I've done over the last couple of years.
Thanks everyone for your encouragement. I am the type of person who doesn't want to fail or look idiotic, and being a novice, I can't help but to look that way! I know, intellectually, that it takes practice, but I want to do it well from the beginning. So then I end up feeling reluctant to even try, yet if I don't try I can never practice....never ending cycle. I need to just go test ride.