This is my wife's iPad. I'm not 100% sure it's on iOS 11 or 12. Probably 11. I’m sure it’s the right passcode. Try a few different passcodes and start getting disabled notifications. Put in the known correct passcode 100 times, it won’t disable, but it won’t unlock. Put in a wrong passcode, disabled again. I'm up to 15 minutes. If I turn it off and back on, it won't let me do anything for 15 minutes - shows the normal "disabled" screen. Do I just need to restore it? I tried having my wife use her thumbprint (this is a 12.9" Pro v1) and it made no difference.