When I was younger I never really thought "Hey, time to be a guy now", I just remember a few very small occasions of where I thought what it would've been like to grow up as boy, but didn't think much more of it, possibly just curiosity? Otherwise I grew up liking things such as pink, glitter, dolls (VERY MUCH including the barbie franchise), wearing dresses, etc., you get the idea. Around age 10 - 12 things changed though. I hit puberty, my body started changing and I wasn't very comfortable with it, but thought "this is normal, you just gotta accept it, this is you now, you can't change it".
Until I stumbled across the Queer Community online, and even though I was usually grossed out by homosexual/transgender people just simply existing, I slowly started to learn and accept them (also mainly because I had a big circle of online mutuals who came out, and I thought giving up those connections for something as small as that isn't worth it).
Later on I started questioning myself, as I didn't feel very comfortable in my appearance, but not just because of insecurities, but also because I looked like a girl, and my name that was given to me at birth also bothered me, not because it's bad, I think it's a very pretty name, but it's just not a name fitting for me. I stood in front of the mirror and experimented with ways to appear more masculine, and felt more comfortable when I looked more androgynous. I was too afraid to ever tell it anyone I knew in rl, I didn't have any close friends anyway, so I spread it around online. I went by they/them online and my old username, and I started to feel more comfortable, but it still wasn't right. I was getting closer but it just wasn't the right thing yet. Until I started to experiment with He/They, and actually also picked up a more fitting name that would've been accepted in rl, and I felt so comfortable for the first time, I didn't change anything on my appearance because I was too scared, but was happy to atleast go online and pretend to be a guy, or it wasn't just pretending anymore, I WAS a guy. I also had pretty long and curly hair and it was hard to take care of, but I didn't really try anyway because I was so tired constantly and doing anything was a big and tiring task, and I didn't go to a hairdresser several years because I had really bad social anxiety aswell. It weighted down on me, it was long, damaged, didn't look good, I'd try to hide it sometimes to look more boyish, until one time I found the courage to finally cut it all off. I didn't shave it, just cut it a bit shorter than shoulder length, but I felt much better afterwards. I finally felt a little more comfortable.
Despite me talking the entire time about how I'm a guy, I still like feminine things, I think they look cute/pretty. It made me question my gender more, thinking that maybe I'm genderfluid or something like that since I sometimes enjoy being more masculine and sometimes more feminine, but I quickly realised that the entire time I said that I'm fully a guy was the time I felt the most comfortable and that me being referred to as girl causes me a bunch of distress. Turns out I just like feminine things and while cis guys already have troubles to be accepted as real guys if they don't fit 100% in, it feels even worse for me/other trans guys.
I am 18 now, it's been years since I've first started to question my sexuality/gender, I'm still figuring things out, but planning on transitioning around age 21, as I have more plans in life and want to be financially stable/be independent first before risking my current job/home.
If you've taken your time to read everything through, I'm thanking you for your attention.