Smoking pot is illegal, and pre-marital sex is not. I think there is a huge distinction.
Being a lesbian is an active on-going situation. I don’t think that compares.
This woman had an indiscretion with her fiance and then she fixed the situation by getting married.
That's the way I see it. Morality means you try to do the right thing. Sometimes you fail. She failed once but did the right thing later. I think it's a great example. Now I can see if the school felt that this might be a bad example for the kids (there are examples of kids finding pregnancy glamorous and trying to get pregnant on purpose, I remember one story of a group of girls doing that). In that case, of course, you still should be discrete.