I’m so happy you’re just starting this journey, buckle up, it will be fun!
Generally there is no point where you “start” to produce original work, it’s just practice. When you’re learning and absorbing information, you focus more on remembering new knowledge and being able to use it in new settings. That’s just how it works when you join a new field.
You will start noticing some logic in the ideas, what leads one thing to another, how structure of your process as researcher affects the outcome of your work, which methods work for you to see the things in the perspectives that can spark new ideas.
At first you won’t be confident AT ALL in such ideas, your subconscious won’t even raise those ideas because they would seem so naive or you will feel imposter syndrome. But with more knowledge and reflection you will start closing those mental gaps, by working with successful more senior researchers you will pick up mental processes that they use and start understanding what is “worth trying” and what is “a waste of time”. Confidence will just be proportionate to amount of time you spent on it.
Of course you won’t be 100% right all the time, but with enough peer feedback you will get into that ballpark area where you can consistently produce high value work.
Just another small but very important point. Almost all of the major discoveries are people being in the right time in the right place with the right tools and INSANE amount of creativity (aka always wondering if a situation has more information than we already accepted as a fact). So with more time you will have more opportunities to spot novel ideas, while hard work will give you the foundation where to draw your creativity out.