And yet, any remotely intelligent person living in a remotely modern country is completely capable of not getting pregnant or getting someone else pregnant, should they choose not to. Let's not completely absolve people of blame just because they're poor/young/whatever. Everyone is capable of autonomy.
Thank you for so concisely and cogently resolving what may well have been philosophy's longest-standing and most ontologically profound line of inquiry. I'm confident that one day I will look back and consider myself blessed for having had the opportunity to effectively witness such an historic event first hand.
It's trivially provable that some vanishingly small percentage of people have no choice in life (e.g. die/incarcerated until death while young through no fault of their own). Accepting that, I think it's logical to conclude that some circumstances will negatively impact you more than others, and affect your chances at success. That does not resolve people of responsibility, but in my mind it does make a case for compassionate handling of poor circumstances.
All I'm saying is, your mouth can't get pregnant.
I remember being a teenager not all that long ago (I'm 32 now). The girls that got pregnant all knew better - I remember sitting through the same lectures in class that they did - but they made their choices.
And obviously you were in the same situations they were, and had the same upbringing, so the comparison is valid? It's nice that you can rationalize your current situation as stemming entirely from all the correct choices you've made, but have you considered that you are far from an unbiased source in such a rationalization?
The truth is that people are not rational actors. Adolescents are even less so. To state that all the girls in your age group knew better when they got pregnant does not immediately point towards them having the wrong goals (or ideas, as you term them), but towards a failure in your reasoning (or at least a failure of imagination).