I always preferred Betty Rubble. 
I remember because I spent summers with my grandmother and absolutely worshipped my Aunt, who would have been 19 years old at the time, and I watched Ghostbusters and Police Academy on repeat and we ate Grandma’s sugar cookies. And we played Lemmings together on the Commodore 64. In short, I remember because it was one of the best times of my life with my favorite people.
It’s weird when I think about how my son is just starting to form long-term memories. What will he remember from this age? Hopefully not my worst parenting moments. The thing he watches most right now is Snowy and Tyler on YouTube and I don’t think he has a crush on a cartoon dog.
Speaking of Police Academy, the guy who played the uptight cop, Eugene Tackleberry, was my other crush at that time.
Or?
Has Ann Marie (Marlo Thomas) been mentioned yet? I had my first ever erotic dream with her the night after That Girl debuted. (i was ten at the time. 
)
That’s a tough one. The earliest I can remember is Kate from The Cutting Edge (Moira Kelly). Later it was Amy Pond (Karen Gillan).
There is much in what you say
I mentioned her as a possible contender for first but ended up deciding it was Emma Peel. I’ll say, though, that my reaction was more like thinking “Hey, she’s real nice to look at,” and I understood why, but no dreams.
When I was 5 years old, it was Clarice the chipmunk from the Chip ‘N’ Dale cartoon “Two Chips and a Miss.”
At the time, I wanted to be an anthropomorphic chipmunk, too (the little chipmunk in my avatar is a nod to this childhood phase).
First in a line of cartoon crushes. My last one was April O’Neil from "Teenage Mutant Ninja Turtles when I was 10.
A real Sportsman’s Double!
I have to go with Emma Peel as the earliest fictional crush I can recall. She was smart, strong, and sure filled out a cat-suit nicely.
That movie is still one of my guilty pleasures. The hockey player is pretty cute.
But I don’t think I saw it until I was an adult.
You haven’t had any cartoon crushes since you were 10? Huh.
Nope. All the rest were real human women. One was on a TV show and one was an Internet celebrity, but they were all real.
Eventually I had crushes on every girl on a sitcom, which I think is their plan when they cast them. So that includes Nancy McKeon on Facts Of Life, Missy Gold on Benson, Staci Keanan on My Two Dads, Alyssa Milano on Who’s The Boss, all three girls on Charles In Charge (Lila, and then Jamie and Sarah, I forget their actor names), and Justine Bateman on Family Ties. And also Joanne Ridley on UK sitcom Me And My Girl.
As for cartoon crushes, only Princess Calla on The Gummi Bears.
I found Midge more attractive than either Betty or Veronica, but wouldn’t have wanted Moose coming after me.
I still don’t have anything for Farah. I had my crush on Jaclyn Smith. Also Lindsay Wagner and Lynda Carter. Closer to my own age was Kristy McNichol, Valerie Bertinelli, Brooke Shields.
In a related vein, pertaining to two of the most burning questions of our times: Mary Ann Summers over Ginger Grant, and Bailey Quarters over Jennifer Marlowe.
Yes and yes! Plus Velma Dinkley over Daphne Blake. Her bob haircut, short skirt, and knee socks really turn me on! 
Yeah. I didn’t realize you were that young.
I didn’t crush on Gadget until a little later as I was a bit too young to notice her at first, I think.
For all I cared, Lamb Chop could’ve been served up with mint sauce, Hush Puppy could shut the f*#k up, and Charlie Horse could be shipped straight to the glue factory. I wanted Shari Lewis all to myself.
She could pull my strings any day.