Yes, it matters - a lot!
If all your family devices are sharing a common AppleID for iCloud, you’ll encounter all kinds of issues with unintentional sharing of sensitive/private information (including your keychain - in which website passwords are security stored). Account lockout is also a serious risk; aside from inconvenience, this may cause considerable pain.
The Golden Rule: Don’t share an AppleID between users. Each user should have their own AppleID for their own exclusive use - linked to their own primary email (and secondary/recovery email addresses and trusted telephone numbers).
You would be best advised to separate your digital identities and configure a new AppleID for the second user:
How to create a new Apple ID – Apple Support
After separating your identities, you can continue to selectively share purchased Apple Services, Subscriptions, Apps and Media using Apple’s Family Sharing features:
Family Sharing - Apple
Set up Family Sharing – Apple Support
Share App Store, iTunes Store and Apple Books purchases with Family Sharing – Apple Support
https://www.imore.com/how-set-up-family-sharing-iphone-ipad
You might be best advised to manually backup any important/irreplaceable data from your children’s iPads - and then to prepare them properly:
What to do before you sell, give away or trade in your iPhone, iPad or iPod touch – Apple Support
After preparing the iPads, set them up from scratch using the correct AppleIDs - and then manually copy any data back to the respective devices.
As for backup and restoring data, you’ll not be able to use the automatic iCloud or iTunes backup - as these will be associated with your own AppleID.