You are right, Velo. It's me. I've been riding a road bike about 5 years; I did my first year on a mtb with slicks. I am very comfortable doing things the wrong way! I know it's wrong, but I am still getting over a life of being uncoordinated, although in my recent, adult life I have been very athletic. I do have documented horrible depth perception, but if i learned to drive, I can do this. Fear is also a big part. Right now I am often stuck riding with people slower than me because although I would definitely say I'm an intermediate rider, my average speed would be a lot faster if i was descending faster. I can climb and I can maintain 16-18 on flats, which may not be a lot to racers, but I am just a fit old lady trying to stay fit. I don't want to be a fraidy newbie forever, but I know with each passing year (I'm about to turn 53) it will get harder. I only wish I had started riding sooner.

You might be right about the core thing. Generally, that has been a strength, but I have let all that lapse during the riding season, i.e. no Pilates, sit ups, weights. I am trying to get back now.
Thanks for the advice.