Does anyone have a way to leave it even if screen sharing is turned on? My dad turned it on my phone but the thing is my mom bought this phone after she got full custody and I thought I wouldn’t have to talk to my dad again but he messed up my phone.

If you are unable to reset Screen Time passcode from the this-> link then, you will need a computer. If you don't have one, borrow from a friend.

Forgot? Click below to reset…

Click->If you forgot the passcode for your iPhone, iPad, or iPod touch, or your ...

Regarding your data, If…

1. You have an iCloud or iTunes backup, I am sorry there is no use of a backup because if you restore from your backup your Screen Time Passcode will be back. 

Set limits for app use

1. Go to Settings > Screen Time, then turn on screen time if you haven't already.
2. Tap App Limits, then tap Add Limit.
3. Select one or more app categories. ... 
4. Tap Next, then set the amount of time allowed. ... 
5. When you finish setting limits, tap Add.

Set up Screen Time for yourself on iPhone - Apple Support