How to protect my Mac from reseting the admin password
FileVault crypts all data on the boot volume. Someone with a physical access to your Mac can boot from the recovery partition but has no easy access to your private data.

The drawback is that even you can't recover your data if you loose your credentials.

Another option is to set a firmware password. This doesn't encrypt the hard drive, but prevents users from booting into a special mode that can be used to reset or bypass a password (typically Single-User, Recovery, or Target Disk mode).


Setup FileVault
Setup Firmware Password