Let me think wayyyyy back to my first bunny that I got when I was 10. I basically knew nothing about rabbits and he was essentially an impulse buy, courtesy of my brother. Thankfully, it worked out very well for Cinnabun and he lived out his life being loved and spoiled mercilessly by me and I'm now a huge bunny lover. Since I didn't know anything about rabbits before I got him, I'll just say:
1) I had no idea rabbits love to eat so much! All of our bunnies have been absolute piggies and will eat pretty much anything, including things they shouldn't.
2) I didn't know bunnies could be so cranky with one another and would attack bunnies they didn't know. Learned this one very quickly unfortunately as two weeks later my mom got me a second bunny to be friends with Cinnabun and it did not go well.