It's always a big deal.
And depending when she took the test, she might take those day after pills, but usually it's too late by then and the only option is abortion.
But mistakes like that can happen, like taking one of your birth control pills late (yes, you need to be on fucking time with this shit or you fucked up) or the condom breaks because of vigorous sex, or it's too old or has a hole in it.
But most teenagers are kinda dumb with shit like that and thinking that pulling it out before cumming or using Coca-cola as birth control.
And I'm not surprised that >>12462678
doesn't know because he might be in a state (or country) that doesn't have health class or the health class teaches only abstinence. I had the latter but I was pretty informed before them because I'm a pervert.