Why do girls get pregnant so young?

Well when a was in school just getting ready to leave there would always be a girl or 2 who has got pregnant. But now since leaving school the amount of girls a use to know WHO are pregnant is shocking am not just talking about 5 or 9 more like 30. You see them all in the shopping centers on a saturday either pushing prams of with huge belly. And a just think why? a left school at 16 got a great job earning good money and it just seems like at 18 they all get pregnant. But at 18 your cled as a adult so a Guess you can't really say that's wrong if they won't to do that, well its up to them. A have also asked some girls why that's sound a bit cheeky but am good friends with them, they just say they felt really broody. At 18 it is very young. I have countless friends who girlfriends have been going out with them for 1 or 2 years and they think that's a long time. so lets have a baby. and it never works out or rarely it does cause all of my friends now have broke with that girl she has to bring the baby up her self and he has to pay maintenance towards her and the baby. so why does this broken record keep playing again. And a have dated some single mum's and its the same story they always tell me got pregnant at 18 he left some months later, and i raised the kid myself. but a ca'nt keep saying a lot of negative things, A think its amazing that a woman can raise a child herself. and i'm a man but if i was a woman and did get pregnant I could never kill a baby living inside me. which is a very hard choice for woman a can't even begin to imgiane the trouble they go through