You make sure she does not have admin rights for starters.
You install WIN 10 Pro instead of WIN 10 Home, which allows you more flexibility to set up group usage policies.
You block access to or prevent Win store from being viewed, accessed, and prevent it from installing anything in the background.
You take on the job of an administrator and regularly ensure the PC is up to date.
Remove ALL, unwanted bloatware from the outset. It is possible, but not an easy process. Susbcribe to a Windows 10 forum of your choice where there are many "experts" around that can assist and help. In my opinion one of the best is "tenforums.com"
And, lastly, ignore ALL the Windows haters that are going to descend on this thread like flies on carcass at a meat shop in Cairo.