How to turn off parental controls? (no family safety option in control panel to turn it off?)

Hello Nxtxliea,

The Family Options has been moved to the Windows Defender Security Center (Creators Update Required)

Clicking on View Family Settings eventually opens your browser for related family settings. Alternatively you can just go to account.microsoft.com/family and login using your mum's Microsoft Account 

Assuming your mum's account is a Microsoft account, your mum might have added your email as a child in her Microsoft Account and that's why it is remembered when you sign in into your computer with the email your mum has added.

The only problem assuming if i read correctly is that you can't login into your mum's account

If so, try to reset the password assuming there was recovery options added into your mum's account here:
https://account.live.com/ResetPassword.aspx

Try checking any related settings here also

More information on Family Options in Windows 10: 

https://support.microsoft.com/en-us/help/10551/microsoft-account-set-up-family-after-upgrade

I think you might need to call Microsoft to get the account recovered because i don't actually work for Microsoft. This community is contributed by anyone so the above steps I provided is the best i could think of.

The best i would before calling is trying 2 out of 3 options provided if you haven't try all of them
1) I forgot my password option 

2) I know my password but can't sign in option. (Based on your situation, you might have already try this so use option 1)

In my situation, I can easily recover because i have done related backup settings in case of losing access to my account