Before I was a writer, Casey, I was a primary teacher, and then a secondary school one. So I've taught students from 7-19 over the years, plus I did did a stint as a teacher of adults (coached a wonderful mum of 5 who had no qualifications to start with, and she ended up with two A grades in English). I measured out my youth in marginal ticks and circles! Show me a grammar book, and I'm a happy woman.