I was on pred for about eight months (40mg) tapering on and off during the whole time. I was sent for a bone density test and found out to my dismay that I'd gone from strong healthy bones to skinny fragile ones, all thanks to the wonderdrug prednisone.
Now I'm on daily calcium and 'D' plus a fortnightly dose of fosavance (70mg) just to ensure they don't get any worse.
My knees and hips are starting to give me some gyp too but I suspect that is a joint/cartilage problem (probably arthritis) and might have nothing to do with prednisone, although it makes you wonder.
I can only hope I never have to take it again.
Considering your age you should be able to get your bones back to normal with calcium.