Indeed, I think you’ll have to go back further than when you were at school. It certainly didn’t occur in my primary school, where girls were the majority amongst the small group of pupils I competed with for number one position in class.
I think it would vary across the country. I’ve been looking for some biographical data on Dr Jocelyn Bell Brunell. She’s about the same age as you and, from what I remember, she had a pretty hard time of it as a girl interested in science. The girls’ curriculum then was cross-stitching and cookery. It’s comparatively recently that girls and boys have had access to the same range of subjects. Before that (in our day) girls tended to be pushed towards things domestic and boy towards industry. Did you have cookery classes at school? Even in my school it was officially called “domestic science”.