I don't think you'll be hindered necessarily, but GML is significantly different from other programming languages to the point where if/when you decide to switch to something else, you'll have to learn a lot of new concepts along with it. However, GameMaker is also a pretty straightforward engine for making simple games, and I definitely recommend it for beginners to learn about basic programming concepts such as variables, functions, data structures and other foundational principles.
GameMaker also exports to most modern platforms these days (including Switch!) so you won't have to worry about being unable to port your games to a certain console unless it's a really old one. The web export is a bit expensive though, so that's something to be mindful of if you intend to make web games from the start.
I say take your time, make something small that you'll enjoy working on, and don't be afraid to ask for help, either here or on the Yoyo Games forums! Unity is a more powerful engine, sure, but it's also significantly more complex and requires more programming experience to be good at it. Starting out with GMS is perfectly fine imo!
(Fyi, I started making games with GameMaker 8
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