This is an interesting topic; after all, to succeed in many fields, to pass that course, you need to be graded. You need grades to achieve becoming an accountant, lawyer, etc. However, is this same with Yoga meditation?
Yoga meditation however, can not be viewed in such a light. Whereas in life we learn that education is a key to success in whatever we choose to do, in Yoga this is far from the case.
Whether you are simply meditating or doing Yoga meditation, the key to success is practice. Often we may neglect such points. We may feel that we need every Yoga or meditation book to help us on our journey. Though these help, books of Yoga on a bookshelf don't give you the skill. And this is same whether that is Yoga meditation or becoming an accountant.
Yoga is about finding that spiritual aspect in a practical way, and this only happens with practice. If you hold to the position that reincarnation exists, then you know that some things may take many life times to master.
Yoga meditation is in similar view with reincarnation. Achieving bliss, the highest consciousness, and seeing past the illusion of Maya is something that can take many lifetimes.
This may make you think that there is no point, if it is going to take many lifetimes, however, that is not the case. The best time to begin is now, if you have not done so already. Yoga offers many benefits, and not just spiritual, though that is the aim of practicing Yoga for many.
Yoga is practical, and one which requires consistent effort. Though the first few times of doing Yoga may seem complicated and new, over time you will get more experienced, and experience the benefits that Yoga gives.
Many people buy books on Yoga, yet so few will ever pick up that book, and sit down and participate. Participation is the key to success with Yoga. And success is another misconception, as success is a constant thing, and not a destination.
Beginning Yoga for yourself can be a simple process. I have found that first getting experience with meditation did help. It allowed the Yoga meditation periods to be more fulfilling. Though you can start Yoga from any age, any place with some peace and quiet.
You can start with one pose and then from there as you gain more experience do more, until you are flexible and balanced in mind, body, and soul.