The steps below will help you discover whether or not you know the password to an admin account on your device...
Step 1 - Click the Apple Menu >> System Preferences:
Step 2 - Click on ‘Users and Groups’
Step 3 - Note the name of an admin account that you normally use to log in to your computer. If you do not have an admin account, your parents need to create one for you using these steps.
Step 4: Restart your computer by clicking the Apple symbol >> 'Restart'.
Step 5 - Log In with the same admin account that you noted in Step 3
If you can successfully log back into your computer, then you know the password to an admin account
Now move on to phase 2 of the process...