Apple Watch Model

Hi,

You can use family setup to set up an apple watch for your child.

Compatible models include:

• An Apple Watch Series 4 or later with cellular (aka ATNT), or Apple Watch SE with cellular, with watchOS 7 or later.
• You need at least an iPhone 6s
• And setup family sharing and create an apple id for your child. https://support.apple.com/en-us/HT201088

More info here --> https://support.apple.com/en-us/HT211768

See here;

Set up an Apple Watch for a family member – Apple Support