Let me apply your little grey cells:
- Support for GMS1 ends next July. This means that if Microsoft or Google or Apple make a game-breaking change in the export platform---Windows, UWP, Android, MacOS, iOS---then your game will permanently stop working. Of course, if you're just making a Windows game, there's a good chance you don't expect this to matter because there's usually a way to make the current version of Windows compatible with earlier versions.
- GMS2's trial is very limited, it is only to see if you like the software, it is limited to 10? objects, 10? scripts, something like that, so it cannot be a long-term choice.
- GMS2 has a very good import for GMS1 projects, so work in GMS1 will transfer over if and when you do upgrade.
- Finally, will you ever have enough money, and the desire to spend it, on the various GMS2 exports that you want? Windows costs $100, mobile costs another $400, etc.
Thus, if you intend to make only a Windows game, just go with GMS1. But if you intend to make a non-Windows game, you will need either to upgrade or not use GameMaker. If you intend to make a non-Windows game and you
will have the money and desire to spend it on the export, then you should continue using GMS1 until you acquire enough money. If you intend to make a non-Windows game and you will
not have the money or the desire to spend it on the export, then you should plan not to use GameMaker.