Start with the asanas is a recommendation also by P. Jois.
The asana practice points at the other limbs of the Ashtanga path: non-violence, contentment, pranayama, concentration, withdrawal of senses, meditation. Yet practicing asanas alone brings a lot of avantages in a persons life. To stay healthy, flexible and strong betters every life.
It was still before 12 when I stepped on the mat. G has a coffee machine now, the one from E. I know how to use it so today I could prepare my cup of coffee by myself. G was out buying some bread. To have a cup of coffee and something to eat is important in the morning. A small breakfast wakes up my inner organs. It's a tabu, but I think it's important to empty the bowel before practicing.
Primary was on the schedule, nothing else. The living room was heated. I had perfect conditions. It was not easy, not at all, but I did all the asanas and vinyasas. No breaks. Deep breathing. And I sweated.
I don't know how I've managed it, but it seems as if I haven't gained weight, despite all the sinful food that was offered during Christmas and afterwards. A slim body makes my practice easier.
My motivation to practice got fresh motifs. I don't think that life must aggravate as it does for most elderly people. It shall be possible to put on the socks till the end of the life. I also want to be able to walk around withoug getting out of breath too soon. As long as possible my body shall be a joy and not a burden. This is only one reason why I manage it again and again to step on the mat and to practice Ashtanga yoga.