I can relate on many of these fronts. To keep my story short: I grew up thinking I was a straight tomboy because somehow I was never really introduced to the topic of sexual orientation or gender identity frequently enough to actually put much thought to how it applied to me. Or I was absolutely oblivious. That's also likely. I wasn't into sex because of also being the "good child" and literally had no idea what was so difficult about just.... not doing it. Fast forward to college and after sort of de-establishing myself from Christianity, suddenly I began questioning many aspects of my identity, starting with gender and identifying simply as "none", and would use "androgynous" for a while until about a year later I became more aware of nonbinary identities, and realized what I was feeling was that I was agender. Later on I started looking at sexual orientation more seriously after I started feeling attraction to more than men (or started realizing it). I think I shuffled between bisexual and pansexual, and settled on pansexual. In more recent years I've continued to shuffle around my asexual identity, feeling like I was just demisexual for years before realizing sex really hasn't been my thing, despite having like a couple years when it was new.
TL;DR, I'm an agender panromantic asexual, and I could find further more intricate labels, but I think this level of specificity is sufficient for me. :u

Having a boyfriend that I've had since high school complicates matters greatly, considering my identities having changed and all that. He certainly doesn't mind the panromantic aspect (if anything, we can both relate to attraction to girls/AFAB people), though the asexual aspect has caused some tension even before I could admit to being mostly ace. The nonbinary aspect has otherwise been okay, transitioning to using neutral address and pronouns was difficult at first for him to understand, but now he's the most consistent about it of anyone. Talk of medical transition has been a bit more stressful, but it's always ended with that he intends to stay with me, even if the terms of our relationship change. Sometimes I wish I discovered my identities sooner so I could explore them more before I got into a more committed, permanent relationship. Though it's a good thing we've discussed polyamory in our relationship as well...

But I also enjoy exchanging multiple different ones too. Although I can specifically use agender and be done with it, I also like genderqueer and nonbinary (the genderqueer flag is also very nice), and nonbinary is generally a good starting point to discuss gender in general. But honestly, I am all down for using any and all that apply to me. I may have already committed to a button collection with a lot of emphasis on gender, but spread out to other interests. Turns out I REALLY like buttons as a way of interchangeable expression.

Either way! Despite my previous reservations about labels, I also learned labels are most helpful in being able to describe specific experiences. If finding a label becomes too worrisome, don't stress about it; but if describing an experience is more important, then do it. And don't be afraid to use more than one to describe your experience, especially if some are more general than others (like using nonbinary, transgender, or genderqueer as general ones, versus agender, androgyne, or others as more specific ones). After all, if it fits and you like it, why not?