Hi Kitty and everyone else that posted on this thread,

I got out a yardstick and a tape measure today and did some measuring to see what I have and know what to look for in my shopping trip when I make it.

Total height of everything, from floor to highest point of mattress at corner is 21 and a half inches. YES, low, but just the perfect height for me.

I also placed the yardstick in various places on the mattress and it does have some sags so I guess I really need to look for a new mattress. I used the yardstick like a level. I really hope I can find one that is not too high.

I measured the mattress itself at the corner and it is 8 and a half inches high so I think I will be OK with a new mattress of equal height or maybe just an inch or two higher.

I am really afraid that a mattress that is more than 10 inches will be too high.

Thanks for everyone's help. I will keep you posted on what I find and what action I take.

Since my mattress does have a few small sags, I think a topper will not resolve any problems that I may be having with my old mattress. I guess I will have to go with a new mattress.