The #firstharassed hashtag is ancecdotal but when thousands upon thousands of women tell the same story, it ought to count for something. All the women I know tell the same kinds of stories. Around the world, almost definitely by 17 but most girls by 12 or so; with some as young as 9 or 10. I was 10 the first time it happened to me. And if you don’t think that catcalling is serious or dangerous, read my article on why France just outlawed street harassment, even though it’s going to be a hard law to enforce.