I purchased my very first Apple product back in December 2023, it's this MacBook Air with an M1 chip, 8GB of RAM
By far, this is the absolute BEST laptop I've ever had in my life, it really is everything I have ever asked for.
Now that that's out of my chest, I wonder what you'll think about this particular laptop's lifetime. Having released in 2020, do you think it'll be sensible to upgrade soon-ish?
What are your thoughts?
First and foremost, you may very well find yourself wanting something with more. Maybe you start doing something that requires more RAM (or you eventually get enough "out of memory" errors that it starts bugging you) and/or storage than what your M1 MacBook Air has. That may prompt you to upgrade sooner than would otherwise be considered necessary.
Barring that (and/or physical damage to the machine not covered by some form of AppleCare), assuming you don't otherwise find yourself needing to upgrade, the thing that SHOULD eventually convince you to upgrade is lack of security update support, which happens two years after it's revealed that your Mac is on its last supported major macOS release.
If the question you're asking is "when will the M1 MacBook Air stop getting support for new major macOS releases", the short answer is that no one outside of Apple knows. Apple, themselves, may not know at this particular point in time.
Intel Macs are still supported. The only two Macs that Apple dropped support for, in terms of macOS Sequoia's minimum system requirements are the 2018 and 2019 MacBook Airs. And, to be perfectly honest, that was much more about the Intel Core i5-8210Y processor that went into both models being a total piece of crap than it was about those MacBook Air models being of a certain age. It's hard to tell how Apple's timeline of when it will drop support for which Intel Macs will shape out, but it wouldn't surprise me if the 2020 Intel MacBook Air will be dropped next for a very similar reason (those were all sluggish pieces of crap that ran like crap and were not reliable).
That all being said, as a tl;dr: While Intel Macs are still supported, so will Apple Silicon Macs that have a base M1.
It wouldn't surprise me if Apple had one or two releases in which Intel support is entirely dropped, but all Apple Silicon Macs (from M1 all the way through M3 Max and beyond) are supported before eventually ditching M1 support.
Suffice it to say, you have several years before your Mac gets left out of a major OS release (and even then, you still have two years of security updates thereafter).