would you?

I told my SO that it's not an option, that we aren't taking in her child. There's no way we could do it and we are currently trying to get out of debt and save to buy a house. Apparently I'm a terrible person for it and I feel like I'm just putting my kids and myself first. Which is what I should be doing as a wife and mom. I feel bad for her child but I'm not willing to burden my life when I'm trying to finish school and do all of these things. His excuse is he doesn't want to see the child go into the system and I understand that but still. What are your opinions? 

Edit. I would not do this if the roles were reversed. We are working to move out of state in the next 3 years and I wouldn't be willing to make my kids suffer over this. Because we would. We all would. I love him but my own kids come first. We are NOT in a position. I wouldn't be able mentally or physically take care of this child and pay for a sitter etc. like there isn't an OPTION. For that. I simply don't have the financial means or the space. Trying to make it work isn't possible. We are seriously struggling and two months behind on rent. Maybe that will help y'all better understand why I am against this. The child is hopefully not removed because of marijuana that would be ridiculous but we are having to have this discussion because of the possibility of it because it just happened to a girl in the same city we live in- I'm not pissed at the answers I'm trying to get y'all to see why I am against this. Because if we take this baby, my children will do without, our future will be put on hold and we will go further into debt. I'm simply not trying to be selfish at all. I'm just looking out for my children's best interest... He is trying to be the hero when I feel being the hero would be making the tough decision of putting his own family first. She purposely got pregnant with this child and knowingly smoked... And won't quit after the birth of the child. She is 36 weeks prego btw. 

The only thing I'm slightly pissed about, is her irresponsibility and selfishness... And I refuse to let someone else's life determine my future for me and my children. I DO NOT want this child and can NOT take care of it. Getting a second job isn't an option because then I'd NEVER see my own child. And I'm not willing to give that up. And then I'd have to pay child care as well. 

I'm not going to sacrifice my kids childhood because of someone else not being a woman. That's how I feel about the situation. I'm asking for opinions on how to handle the situation...