The key words are 'gentle stretching'.
If you feel you are overdoing it then the answer is easy - stop. When your body has recovered and healed you can try again but this time being gentle with yourself. There are no prizes for going at it like a bull in a china shop and you will regret it if you do.
Reaching a 'happy medium' for yourself is the key rather than striving to do what others do. They may have been working at it for a very long time!
blessings