Shacking up...

How does everyone feel about “shacking up” or living with your boyfriend before marriage? I am 22 and he is 26. We’ve been together for almost a year. He already has his own apartment and I still live with my mom (I’m a college student) but we have been talking about getting an apartment together once his current lease is up. My mom is a strict Christian and is totally against it. She says that we will be living in sin but I have read the Bible and I don’t see anything in the Bible about “shacking up” I want to know what are you guys opinions on living together before marriage