Before giving away the iPad, or reusing the iPad with a different User, your should properly prepare the iPad:
What to do before you sell, give away, or trade in your iPhone, iPad, or iPod touch - Apple Support
After wiping the iPad, it can be set-up again as new. Wiping the iPad will not erase the currently installed version of iOS/iPadOS.
With iOS12.5.5 installed, you clearly have an iPad Air1, mini2 or mini3. Apple ended major update support for these models of iPad in September 2019 - although they continued to receive “point” security updates until late last year. These devices cannot be updated to iPadOS 13 (or any later major versions of iPadOS) as the internal hardware does not meet the minimum technical requirements (CPU and RAM) for newer versions of iOS/iPadOS.
You may find this information to be helpful with setting-up an AppleID for a minor - and perhaps considering appropriate controls:
Apple for Kids - Official Apple Support
Help your child set up an iPhone, iPad, or iPod touch - Apple Support
Family Sharing and Apple ID for your child – Apple Support
Use parental controls on your child's iPhone, iPad and iPod touch – Apple Support