I don't remember the exact date/month/year/age of me becoming a brony (or watching the show). It's a long story, so get comfortable.
A lot of girls at my school liked MLP. I thought it was the weirdest thing. Even this girl that considered herself a tomboy watched the show, I despised them.
I've always loved the show The Fairly Odd Parents. If you guys didn't know, Tara Strong voices the main character. I love her work. I tried watching every movie/show she was in.. and I came across MLP. I still ignored it and pushed it aside.
Our cable finally got the Hub, and I started watching it and came across MLP. I decided to just watch an episode. I don't know the specific episode, but it was an episode in season 2. I do remember "The Last Roundup" being ONE of the first episodes I watched.
I wasn't majorly obsessed with the show, but I still really liked it. One of the reasons why I started watching MLP was because of all the girl bronies at school (I don't like the word "pegasisters" ). I had a guy friend who HATED me liking the show. I didn't care. His little brother liked it too. I remember sometimes we would watch it together
I remember watching the season 2 finale just when it came out. I moved to another state a few months after that. That's when season 3 started, but I didn't have the Hub so I couldn't watch MLP. It wasn't a big deal to me.
A while later (actually, a few months ago) I was on YouTube, and I came across one of my favorite PMVs by YBH and I thought "Wow, look at those scenes. Why didn't I ever finish watching this show?". So this summer, I've been watching all the MLP episodes (even re watching a couple since I've already seem them). NO REGRETS. I loved it. I loved the show even more than I did before. I also started watching fan made things like music, animations, artwork, analyzing videos, etc.
So yeah, that's how I got where I am today.