Adding to Anssi’s answer, with 2017 things were changed. Before that, the one and only download starts as Pro and ends up either as Pro or Make, depending on whether you buy the Pro license. With 2017 there are two downloads (both on this page: https://www.sketchup.com/download/all
The Pro 2017 one is Pro, and if you don’t add your 2017 Pro license, it will stop working after the trial period. The Make 2017 is more like the older type, it is going to be Make, but starts off with Pro features. If you add a Pro license it does become Pro, but otherwise you reach a day where you have to click an I Agree button to agree to only be using Make for non-commercial things.
I don’t know where it is written, but somewhere we say that you can’t mix versions. That is, if you had five people, four using Make to create models, that the one Pro user includes in paid work, that wouldn’t be allowed. In your case, if your Pro license is only used for non-profit work, and you also use Make on another machine for the same non-profit work, that should be ok (but I’m not a lawyer!).