Be careful - this was me back in the Diablo II days when I was in middle school. It's great because it got me into technology but the downside is it's extremely easy for kids to stumble upon a virus this way. Hopefully you have some safety measures in place.
Getting a virus on your (adult) personal computer can be a really big pain due to potentially forcing you into losing valuable data (tax records) or needing to sink a lot of time into recovery or reconfiguration; back up your data! For a kid I'd generally run with the assumption that they're going to software brick their computer at some point and just hope they don't overheat the computer in the process. Be prepared to reformat and reinstall operating systems, and, if you can, grab a cheapo computer dedicated to your young ones and keep them away from the "important things" computer.
There is alot of content to be potentially loss that could be important through out someone's life that aren't financial.
As an example there are basically no hard copies of photos and videos now so a kid could potentially lose any memory of their child hood they didn't share on a social network or that their parents didn't document for them.
Facebook encouraged uploading of full albums when it was popular but all of current tools heavily encourage curation to project an image or that for fun images are ephemeral.
There are tools that help mitigate this like dropbox and iCloud, but as far as I know they only save images taken on the device and not images sent to you.
