Oooh, there was a girl in high school (she was eighteen) that was pregnant! It was lovely, really. In her case, she went through the year like nothing was wrong, she got good grades and when the baby was born all the class brain-stormed to find a name for the kid.
This is to say, I don't see what the problem is.
No, I'm not saying "let our poor, innocent teenagers have children" and no, it's not the choice I would have done. I'm saying that if they chose to keep the baby and are happy with it, why should it bother you?
I mean, you are fifteen and pregnant. Whatever. It's not age that makes a good parent- and besides, it's not like it means that "omg you can forget every kind of dream you had forever", it just means that it's, well, a little bit more difficult to reach. Not impossible: difficult.
Or maybe they'll be happy just with the kid. Dude, it's not like everyone cares about being a big shot and having lots of money and going to university and whatever.
And c'mon, now, what do you prefer: a happy pregnant teenager, or an angsty annoyance that keeps repeating "bu-uh, not me, why did this happen to me?" every day, on loop, 'til the end of time?