There are young people today that move like old people from eating too much junk food and not getting enough exercise.
Always remember that Nature refuses to be rushed. She can only be made to evolve and that takes time, so take heart.
You have to get serious about your practice!
Don't teach too many postures; just the main ones, and hold them for a long time.
Don't worry. These poses have nothing to do with meditation or enlightenment.
Yogis love to be alone.