Systems Preferences Won't Unlock

I have a Macbook Air, it uses the current Big Sur OS, and I was trying to change some settings in Systems Preferences, but it just would not let me even though I typed in the correct password multiple times. Am I doing something wrong? Is my password invalid? if so, what do I have to do make it valid or make it authenticate and unlock? Or is it something wrong with the computer itself and has nothing to do with me? If so, what can I do to fix the problem and get System Preferences to accept password and unlock to make changes to the setting?