Not really, I am learning them in Yoga now and I am 37. Its muscle memory, you have to start slow and make sure you don't injure yourself. You are definitely more open/flexible when you are young and can learn it a lot faster, but as an adult if you take your time, you can still do it, if that's your goal.
It's where u stretch to do them often that makes u able to stretch further so it more comfortable
Are you reading my mind!?!