It depends on the way you like to learn.
If you like to play around with things and look things up as you need, go with a beginner-friendly distro (Mint, ElementaryOS, and Pop!OS are all good options). This gives a more immediate payoff (in that there are lots of fun things to experiment with right away), but you'll learn things kinda piecemeal.
If you like to learn by reading first, then starting with the absolute minimum and gradually working your way up, something like Arch might be great for you. It's a much slower process and has a much steeper learning curve, but if you have the discipline for it, you'll come out with a really solid understanding of how things work.
Most people start with something simple, and venture into the more intimidating waters when they feel comfortable. If you're not sure, try Mint and go from there. You can always wipe it and install Arch later (if you don't have anything important on this laptop, you can try lots of different ones without worrying about migrating or losing anything).