I believe Joel Gilbert’s film says the age of consent in Hawaii in 1960 was 14.
I did not know that. It is quite possible. I believe other states also had age of consents that low in the past. But here's the salient point. Could it be that the man who got her pregnant did not know the age of consent was so low?
I find it rather coincidental that she became pregnant right at the time of her birthday. (November 29.)