Practice these poses on a regular basis and you will have very little problems zipping up your dress, washing your back, reaching your hind parts (lol) etc when you get older. Or if you are having those problems now the more you attempt to do these, or even simply grasping your hands behind your back, it will get better.
Someone is going to say “I can’t do that!” Well, yoga is not whether or not you can do a pose exactly like it’s done…it requires that you do the best you can and work your way to the pose or as close to it as you can. Over time, you can inch your way up to the middle of the back. It’s a slow process.I still can’t do either one of these if you are judging by the photos on the right. Yoga’s a no judgement, no competition zone. You may not even be able to close your hands all the way. And the other pose, where arms come around in opposite directions to the middle of the back, you can use a towel to gently pull up.
~Nikki
Nikki's Confetti Life 
Great post – I’ll try these today!
Thank you! You’ll be glad you did.