judgmental sister in law

So I moved inn with my boyfriend on January. Only his parents and his little 10 yr old brother live there. The oldest sister lives in the back house and the other youngest  lives across the street from his parents house in a small studio as well. Most of the time they're at my in laws house (my house). My boyfriend and I are going to 4 years this year. He turns 23 and I turn 21. Well I was having a convo with his mom and I told her if my boyfriend mentioned to her that we bought our bedroom set that we will be receiving this week. And the youngest sister heard and she gives me this surprising look and asks, "when are y'all gna move out??". (She's 24 engaged, getting married this year) I recently had a miscarriage as well and my job accepted me back which I start this upcoming week as well and I responded, "I start work this week so that'll help us more". And she says, "yeah it's better to have your own space and privacy. Just don't get too comfortable living here". I felt like my heart dropped. Like why did she just have to throw it out there.  We do plan on buying a duplex with my parents. We're just trying to save up more.  She always tries to put me down and my bf (her brother). She feels like her live is so perfect. I miss my home, my little siblings, my parents. I sometimes feel like I'm doing the wrong things in my life. Any advice ladies.... or what do you guys think....