I was but I wasn't. I wasn't vocal about it in the stereotypical way-- instead of complaining about people calling me a girl, I cracked jokes about it. I had the perfect joke material: Throughout most of her pregnancy, my mom expected I was going to be a boy. As soon as I found this out (at a fairly young age), I took it and ran with it.
"I was supposed to be a boy, but I ended up a girl instead."
"I was going to be a boy, but my body got switched before I was born, so now I'm kind of both!"
"Before we were born, I was the boy and my brother was the girl!"
...I had a whole series of jokes like that. It was all said in good humor, but I always made it very clear that the aim of the joke was not "Haha, they thought I was a boy" but "Ha ha, I was a boy and I got switched."
However, I didn't learn until a lot of years later that my joke could amount to anything more than me joking around. Before I hit puberty, I was never really bothered by being in a female body-- I just found it amusing. What can I say? I've always been fond of irony!