Second word of advice: Older women can be absolutely fantastic lovers. I concur with draining the tanks beforehand - should really help lengthen the encounter. Don't be surprised if you get completely worked up and pop early the first time you are with her though, primed pump or no primed pump - that's normal when you are in such a sexually exciting situation as the one you are describing. Don't worry, you'll settle into a nice groove with her very quickly.

Enjoy. I know I did when I was in your postion.