I wear bifocals and have never had a problem shooting a scope with them. I focus the scope with my distance (top) prescription.
norad, I assume you are either wearing bifocals, trifocals or progressives since you mentioned age... I could never get used to trifocals or progressives and would think they could be problem looking through a scope as you'd have to be using the exact same point on your glasses every time. I also always have my bottom prescription placed a little lower in the lenses than recommended, which helps me "keep it out of my way" when walking, shooting, etc.
If you're using trifocals or progressives, consider trying bifocals instead for shooting. If you are already using bifocals, is it possible you might be "splitting" the lenses when looking through your scope? If so, a lower placement of your bottom prescription might help?