The character was nonchalant about it so I wonder how everyone else are.
Personally, I found out about it when I had this crush on a classmate who's cute and handsome. This was when I was in Kindergarten (6yrs old)... It didn't freak me out but rather I thought it was something normal. Like, I thought everyone else knew about it just like how everyone just know that a girl likes a boy or something like that. I thought that way until I was 10 yrs old when my classmates teased me for being "too girly and weak". That's also when I realized everyone makes fun of and hates gay people.
P.S. I still have a crush on him though even now. We've been classmates and/or schoolmates through grade school, highschool, and college, seriously. xD
I have somewhat always known that I like girls and some years ago I finally found a word for it. So pretty much the same reaction as in that manga reply