Moving in?

My best friend (for the past 9-10 years) asked me to move in with her boyfriend and their 2 children. One is a year and a half the other is a newborn. While I love the idea, idk if I should. I don’t want to seem like I’m butting myself into their life but at the same time I want to move out of my parents house. I love kids, they’ll let me bring my dog, they’ll let me cook (which I love), and everything else. But I don’t think my family would be supportive. They offered to let me move in since their current roommate is moving out. I have until June 15th to decide but I’m not sure what I want to do. They have explained everything, even showed me the room but I’m not sure if I should go through with it only because I don’t know if I have my family’s support. Any advice?