Salma Hayek...in 97 she floated down a river in an innertube on Fools Rush In and I was hooked. She is my longest and most enduring woman crush. I wanted to look like her or fuck her - or both - from the moment I saw her.
My second grandest woman crush is Monica Bellucci and I've adored her for nearly as long.
As for "real" people, I found numerous girls and women attractive from the time I was 12-13ish. None were long term things though until my late teens.