Yeah, that part sucks. She started on Loki (not that she knows that) and I upgraded things to Juno and that was enough for me. Luckily, her life on the computer is a printer driver and a browser window, so there wasn't much that needed re-configuring.
IIRC, my biggest complaint about eOS was that you could not upgrade it between major versions, and had to do a clean install every time.