Hi, Seed,
One important thing to remember with Cathe's stuff is that you can modify, modify, modify! The choreography in some of her more intense tapes (like Interval Max, and bodyMax), is actually a BIT more basic than some of her others. It is just that there are so many power moves and plyometrics that make them SOOO intense. But, you can make many of her moves low impact, or substitute with other moves UNTIL YOU ARE READY.
As for step height, I use 6 inches as do many others, even Cathe in several tapes. Many say that they can get a better workout with a lower height because they can really put more into the work without worrying about tripping. That is a purely individual thing! At times I use no step at all to save my aching knees.
Several of the women on this site are in their 40's and 50's, so don't let that stop you! But on the other hand, go at your own pace without comparing your self to others
I agree with MIS as a great suggestion for Strength Training. The Pure Strength series is wonderful, too. I think what really gets people through plateaus is mixing up their workouts every 4 to 12 weeks...so getting all of her tapes is a great idea!!
So, this is just a bunch of info, with nothing specific to tell you...if you need more help, just let us know!
Wendy
PS--Hope I didn't put you off The Wedding Video--it may be just what you're looking for as far as basic stepping, and it is very intense! Also, the strength section always gets my arms shaking, even though the weights are lighter than anything I use for her other tapes...