I remember deciding, at age four or five, that I loved jeans and wanted nothing to do with sweatpants or leggings anymore. No more skirts or dresses, either (not that I had many; pragmatic mother, cold climate). I remember always having a favorite graphic tee. The first one had watermelon slices on it. Then I got a t-shirt that just said "Not!" on it in big letters (early 90s -- remember Wayne's World?). After the slogan tee came one with a kayak graphic (I grew up on a lake).
In elementary school, I collected hats (mostly bucket hat styles -- it was the 90s); we had "hat day" on Wednesday, the only day we were allowed to wear hats inside, and it was my very favorite day of the week. I had one hat that I decorated with cute little tack pins (mostly animals -- people knew I loved them and I received a lot as gifts).
Once I started school, I became very shoe aware too. For a while, Adidas Sambas were The Thing (soccer was really taking off at this point in my community; we all loved those silky Umbra soccer shorts, too). Then skate shoes; Vans of course, and also Airwalks, which purists insisted was a copycat brand. I'm sure I owned both at some point. Then by high school I was all about Chuck Taylors, and that persisted into my 20s 'til my feet couldn't tolerate the narrow rubber toes anymore. Along with Converse, my other big obsession in high school was messenger bags. Not as practical or ergonomic as a backpack, but so much cooler! I had a pink YakPak, then a Timbuk2 later on.
In terms of clothing, I settled into a loose tomboy-prep aesthetic and haven't really deviated from it too much to this day. Solid base of jeans, khakis, corduroys, mariners, graphic tees, and button-downs. In middle and high school I thrifted virtually all my own clothes and ended up with some wacky one-offs that I adored for their novelty: a black velvet mini skirt, a couple pairs of palazzo pants and drapy gauchos, some boho dresses, and some "ugly" sweaters and chunky "grandpa" cardigans.
I was never a magazine reader and any awareness I had of trends was based on observation and intuition. I've never felt much pressure to "fit in" and have always been happy to exist a bit outside of the mainstream. I always had a strong sense of what I liked, what I was excited about, and what I was tired of, which sometimes aligned with what was current and sometimes not. I might be somewhat more trend/market conscious now because following fashion has become a bit more of a hobby for me, but really not much has changed!