How do I disable screen time if I dint know my password

Click here: If you forgot your Screen Time Passcode or watch this video:

If the above doesn't work, when you first create a screen time passcode it prompts for an optional Apple ID to recover the passcode if you forget it. This doesn’t have to be the same Apple ID that the phone is using; it might be a parent’s Apple ID, for example. This is the Apple ID you need to reset the Screen Time passcode. If you didn’t set one up (it IS optional) or don’t know that Apple ID then you can’t recover the screen time passcode; the only option is to set up the phone as New.