Hey George - ever reset a Mac?

[Mik]

Daughter does not remember her password. Probably not her ID either. Have you ever used Apple's Recovery Mode? If so did it work as advertised?

[Klaus]

That's a typical Windows problem. Get a Mac!

[George K]

@mik Recovery mode allows you to restart the computer using the internet as a boot device (or the hidden partition on her hard drive). If she has an Apple ID, she should be able to get a password reset and/or a username reset from Apple.

https://support.apple.com/en-us/HT201354