Ubuntu is the name of the Linux distribution made by a company called Canonical. It is one of the widest used distros. It is a very good distro. But the 'window manager' (which is the graphical part you see, in the same way you see windows in Windows 10) is a little different to what most users are used to.
Linux Mint is based on Ubuntu but supported by a much smaller team. Because Linux is open source anyone can take an existing distro and change it. In the case of Linux Mint a small team have taken Ubuntu and replaced some parts of it to try and make it a bit more user friendly to people who are used to Microsoft Windows. Mint is the distro I usually recommend to first time users because:
1) It looks like Windows.
2) It is based on Ubuntu and most tutorials and commands that work in Ubuntu will also work in Mint. Ubuntu is so popular that it is one of the distros where it is easy to search for 'how to' articles.
There are several flavours of Mint; Mint Cinnamon and Mint Mate. The two look very similar but Cinnamon is designed for slightly newer hardware and looks very slightly prettier. Mate is designed to run on lower spec machines and still looks great but not quite as pretty as Cinnamon.
Either Mint Cinnamon or Mint Mate will be fine for a first time user. I use Mint Cinnamon on my laptop. Because this will be in a virtual machine I would recommend using Mint Mate as it will be running with fewer resources.
Extra info...
1) Mint Mate is actually pronounced 'Mah Tay'.
2) Just like Mint is based on Ubuntu, Ubuntu itself is based on a distribution called Debian which is again maintained by a small team.
3) Although Linux can be made to look like Windows, don't assume it always works the same way. There will be times when you get stuck or confused. Just Google for an answer or ask soneone (such as here).
4) Welcome to Linux