Not because I love blue more than any other color -- I love lots of colors. Red, for example. And purple. And black, and green, and brown... And I love any number of combinations of colors: Black and brown, yellow and white, green and grey, green and orange in spite of not particularly loving orange.
That hasn't always been the case. Not loving orange, that is. When I was in first grade my favorite outfit was an orange and yellow one my mother made me, and for the art contest that year my drawing featured a lot of orange and yellow. Everyone's drawings were hung in the hall and when I got to school the morning the ribbons had been awarded I rushed to mine to see whether I'd won anything. I had! -- an orange ribbon, which was nice since it matched the picture, but puzzling. I knew what a blue ribbon meant, and a red one, but not orange. Then I noticed something strange. All the pictures had ribbons and the ribbons coordinated perfectly with the dominant colors in the work. So I understood: The ribbons didn't mean anything.
But, back to blue. People like to ask kids what their favorite color is, and they expect you to have an answer, and if you say, "I like purple and green and yellow," because you happen to be standing next to a flower bed featuring that particularly lovely combination they'll say, "But which one do you like best?" So you have to come up with one color that you like best. I'd noticed that most girls my age liked pink the best, so I decided that blue would be my favorite.
Learning to navigate the questions asked by adults is just part of growing up. By elementary school I'd learned that "A mommy" was the wrong answer to the standard "What do you want to be when you grow up?" question. I amused myself by thinking up various careers and trying them out on the grown-ups to see which ones got the best reaction. Conclusion: It didn't really matter which one it was, so long as it wasn't Mommy.
Grown-ups are so strange.