I wouldn't say anything to her. It will probably stress her out and you don't want that of someone who is pregnant. I'm sure she's stressing out already, im sure shes already thought of all those things you mentioned. If i were you i would be a very supportive sister and just listen to her. let her know you are there if she needs to talk

I totally get your concerns. Just because she will have a baby doesnt mean she wont finish school. And even if she decides not to go to school that is her decision. Sometimes your hopes and dreams do change when you have a baby and theres nothing wrong with that. I kinda felt sad when my sister got pregnant at 16, but she managed to finish high school and is now in college. Its been hard but shes managed fine. If your sister really wants to go to school she will make it happen! I hope you can find a way to just let it go and be happy for your sis