How to login under admin if I can't remember my password

Hi,

1. Restart your Mac. ... 
2. While it is restarting, press and hold the Command + R keys until you see the Apple logo. ... 
3. Go to the Apple Menu at the top and click Utilities. ... 
4. Then click Terminal.
5. Type “resetpassword” in the terminal window. ... 
6. Then hit Enter. ... 
7. Type your password and a hint. ... 
8. Finally, click Restart.

or

https://support.apple.com/en-us/HT202860

I have tried this 3 times and it still isn't recognizing my NEW password.