I bought the Coles 3 easy steps dvd - the one that's $7.95 or whatever and that has the healthy eating tips and a yoga class and a pilates class. I did the yoga class and it is not for beginners!!! I have done quite a bit of yoga and pilates over the last year (and although I am still pretty weak and my balance still needs work I do know the most common poses and can manage them without too much hassle) and doing this class I actually fell over 4 times, and I strained my neck and shoulders. It is a great workout and if you do a lot of pilates and yoga then it's certainly worth a go, but I went into it expecting it to be introductory and easy and it certainly isn't, so just be warned about that!
There is never a wrong time to do the right thing