That's what I was thinking. I remember CS101 at my school had a decent amount of women, but by the time you reached 3rd year they all had disappeared.
"I want to make games!" to "This shit is hard, I'm gonna get a business degree."
As it happens when you have projects that take about 4x (or more) the amount of time as your friends majors that takes a toll. People would rather be partying than writing code. Maybe our CS1 was a bit too hard (we've had many discussions with the profs about this and the attrition rate and what to do about it), but everyone who finished freshmen year graduated in our class. It prepared us well, but it was too hard for most.
"Angersock," he said," do you know how many women there were in my first year?"
I thought for a second. "I don't know, maybe 20 or 30?".
"About half my class of around 80 or so. Do you know how many I graduated with?"
"Erm, 10 or 15?"
"Try 3. Does the phrase 'hunted to extinction' mean anything to you?"