1, Find out whether she needs any specific piece of software that is hard to replace. 2, Regarding distro, you should install her what you use, so it is easier for you to help. Ubuntu is well hated for a reason though (Canonical doing big tech things). I'd recommend either Linux Mint or Debian (if you are not a beginner in Linux and comfortable in the termunal) for both of you, but I'd wait until she passes her exams and may consider setting up a dual-boot on a spare SSD first, so she is able to try Linux and go back to Windows when needed. 3, Desktop environment: GNOME is considered best for ones coming from Apple and KDE from Windows. Both are resource hungry in my opinion, so I use MATE, which looks like GNOME 2 out of the box and uses a bit more resources than Xfce, well configurable though. Note that Ubuntu MATE is its flagship edition, many options are there out of the box (like MATE tweak).