Family Dinner Gone Wrong: Dealing with a Difficult Sister-in-Law

long post ahead!! sorry about it but i needed to let it out. if you have advice i’d love it. to preface this: me and my bf are 20 and have been together almost 3 years. i was invited over to his house for dinner with his family. i was excited to see everyone because i hadn’t for a while, but nervous because last time i saw his sister she was not very nice to me. things were going well at the beginning of the night. we had a nice dinner and i even felt like me and his sister were bonding a little. then his parents (who have always been extremely kind to me) went to bed. we somehow got on the topic of plans after graduation and i made a comment that me and my bf have discussed moving to the same place she plans to post grad. she told me i was wrong, that my bf doesn’t want to live there and instead wants to move up north. this is something he’s talked about doing once we save money, but we both know we don’t have enough saved to move so far away so soon. i tried to take this in stride, while also keeping the conversation fun. i mentioned that we could move there once we found our footing and made a little joke about moving overseas together. she was very offended by this, saying it was a horrible idea to move overseas together because of his desired career. i made a comment about how he’s not particularly sure of what job he wants right out of school because his dream career won’t make him much money right away and he doesn’t plan on going to grad school like she or i do. she told me he doesn’t need grad school and that he’ll be fine without it (i’ve never pressured him into grad school and agree he doesn’t need it to find success). then she tried to tell him what career she’s always thought he should pursue (it is not what he wants to do) and then turned back to a different conversation while we continued talking about our future plans. then she yelled at both of us for having a side conversation rather than joining in hers. i’m not a person with very thick skin so this really hurt me. i excused myself to the bathroom where i cried for a little and then decided to go home. i left without really saying goodbye to anyone. my boyfriend is livid that she made me cry, but also says that’s just the way she is. i want to marry my boyfriend, but i don’t know how’ll i survive this my whole life.