Unsure of how to handle my roommate

I am 15w pregnant tomorrow, my roommate who will also be my SIL is about a month and a half behind me. She is so completely misinformed about pregnancy and it breaks my heart for my niece/nephew and brother in law, as none of us can get any sense into her. She is still smoking half a pack a day and states she will continue to do so until the second trimester because she truly doesn't believe her actions affect the child until the placenta forms. She is also consuming 500+ mg of caffeine daily, because that is the "recommended amount". We've subtly and not so subtly shown her helpful articles and facts but she totally disregards us. It is unnerving to live with. She will still smoke in the car while i am in it! Is it time for me to give up?