Over the last few days, I've been helping one of the students in my lab edit his thesis (grammar, not content). It's been a collective effort of the group, with several of us working on different chapters. Through this process, I've discovered that I am apparently much faster at it than my native English speaking peers.
I know roughly when I picked up this skill. In high school, I was a grader for freshman English for 2 years, and I graded chemistry lab reports for 2 years as well (there was some overlap in there...). I had just never before realized that I was particularly good at it.
What skills do you have that you didn't realize you were acquiring until much later?