no problem! i came to that conclusion because for the longest time, i never quite saw myself as female. when i was young, i preferred a lot of typically male titles (ex. i wanted to be a husband and not a wife) and when i would imagine how i would be as an elderly person, i always thought of myself as an old man. i was a tomboy type. i liked to play in mud, i'd spit on the ground, i liked video games (which growing up in the 90's/early 00's, that was seen as a more male thing to do ofc), i wanted to pee standing outside lmfao, i preferred boys clothes to girls (though now i look back and think that maybe fashion was just bad then and honestly yeah it was). you know all of those times i had my gender listed as male on here? ughhh it was so relieving when people would think i was actually a guy. i mean saying all this now you'd think i'd have ended up a trans man. but i grew into my femininity later. much, much later. i finally liked feminine clothes, make up became very fun and freeing and expressive, pink was suddenly The Color. ofc i want anyone reading this to understand that none of this stuff makes you exclusively male or female (see me for example) but finally growing into what i had long been socialized for had me thinking if i had just been in a phase all of that time as a child.
and then i realized...nah. it wasn't a phase. just part of the road to self discovery lol. after a while of thinking i was too girly for the boys and too boyish for the girls, i largely decided you know. maybe i'm both. maybe i'm neither. something in between? i found that nonbinary best suited a way to describe myself. aha at some point i was convinced i was basically just a gay man with a female body. admittedly my body still makes me feel dysphoric at times, but there are some days i'm totally fine with it. not enough that i would ever get surgery over it but u kno. if i had to really, really pinpoint myself down, i'd say i'm more masculine in terms of mind, i just present very femininely. although i'm fine with any pronoun, if i had to rank them in terms of what i want to be referred as, it'd be they > he > she.
as far as compared to agender though, as i understand it, agender seems to be like. the lack of a gender? so you know. like. a starmie or a solrock. they don't have a gender. to tell you the truth though, i'm not so sure where to draw a line between the two. agender seems to be lacking, nonbinary seems to be like...you have a gender, it's just not entirely male or female (ie. not on the binary). that's how i'm looking at it anyway? sorry if this is not helpful aha.