I was looking through the only personals site that i use frequently and have an account on. I did the broadest search categories i could for my area and just started going through them one at a time.
There were indeed girls who seemed geeky and interesting and cute and into science fiction or video games or anime. And they were all 19 or 20.
Clearly these girls exist, however by the time they get to my age they're either involved with someone, or been made very aware of their own worth and know that they don't need to bother with something like personals.