With my fitness enthusiast's hat on
From what I gather, it's not so much how well you can do the physical position that matters, but the mental attitude during the position. I did yoga a long time ago in a place where it was not demanding at all. And it was very, very good. It was taught by a tibetan buddhist monk. And I knew people who did yoga at physicaly demanding places and it seemed that they almost didn't like the classes.
So advanced posture is not that important to me. A very good teacher who really knows what he's doing is more important to me.
I am taking care of my weight problem. It's going well.
It shouldn't be much more time until I can do yoga well. I will try to incorporate more stretching in my exercise.
(yoga, soccer, middle distance 5 km runner, swimmer in high school, weight lifting and bodybuilding between 18 - 25, back to runner and bodyweight strength training from 25 - 33, trying to become a runner again now at 40)
Why do you want to do yoga?
Yoga has 4 uses - repair some types of injuries if you are a professional athlete, help with managing problems like spondylosis (it is very effective in treating vertebral herniation), fitness activity for those who are full time yoga / fitness gurus (in the sense they will be doing it for whole life few hours a day), meditation (see below)
Yoga has no benefit on the mind (except when used as Hindu meditation, see below). It does not make you fit (in sense of reducing weight). Someone who has done it for decades from childhood may get some health benefits but anyone who is above 30 already has damaged liver, lungs, spleen, spine beyond repair even if they never drank or smoked. All humans above 30 have damaged their body and it cannot be restored to that of a 8 year old.
Hindu yoga gurus claim that it cures diabetes, thyroid problems etc. It is hard to see how an act of contortion can cure a gland of malfunction. Then no circus contortionist would ever have diabetes.With my Buddhist hat on
This is not to discourage you but a sincere question since being a Buddhist you are used to mindfulness meditation. Yoga leads to another type of meditation entirely - Hindu school of meditation where the aim is to make the Kundalini rise from coccyx to forehead (mooladhara chakra to sahasrara chakra). Due to this the practitioner supposedly gets magical powers and under a proper guru may advance on the path of moksha (see hatha -----> feeder to raja yoga below)
Since magic is dismissed by Buddhism and even if magic happens it is another sanskara why would you want to wet your feet in that pond.
There is nothing yoga can do for you that running or working on elliptical along with serious stretching along with samatha cannot do (with less headache of having to learn a new system from scratch)
If you do not believe me google "Fauja Singh". He is a Sikh who began running at age 80 (because he was bored of looking after his grandchildren) and became a marathon runner. He is a healthy 103 now and still runs to keep fit. No offense to any yoga guru but I would like to see them run 5 km at age 60. At age 102 Fauja had to be convinced to give up his habit of running 10 km. He was not very happy about it. Yoga gurus claim an inner fitness (meaning their organs are better functioning; but there is no such proof that anyone who does yoga will have better endocrine system. Why not also say circus contortionists will never have diabetes then!!).
I am the guy whose nation is birthplace of yoga and I am the guy who is saying that yoga for a Buddhist is just adding to chores with no real improvement in benefit. If you were a Hindu who was interested in getting Kundalini to rise to sahasrara chakra .. I would have said go right ahead.
Just voicing aloud some points. No offense meant if you want to practice yoga. Note - Yoga is not to be confused with yogi. Yogi is a person who uses any of the Hindu paths of moksha but usually used to mean hatha / raja yogi. There are 4 paths jnana yoga, bhakti yoga, raja yoga, karma yoga. The yoga you see is part of hatha yoga which is supposed to be a feeder into raja yoga. It is so complicated with numerous feedback loops in flow chart that I doubt any Indian at all understands it.
In its most esoteric form you can see hatha yoga in Tibetan Tumo meditation where they can make a wet blanket dry by heating up their body. But as a Buddhist we are not trying to make wet blankets dry.