Should I call off the engagement & break up with my fiancee?

I've been secretly engaged to my fiancee for about a month now, but recently I've had time to think about when it comes time for her to move in with me...as it is right now, she's 27-still lives at home with her parents-does not have a job, only volunteers at an animal shelter & brings home $15 a week-does not have her own car. All of these factors, combined with trying to pay off my debt, has made me rethink the whole engagement thing. I love her to death, but the fact that she's in this particular situation worries me; she knows I've thought about this and told me that I worry too much. I do worry too much, but I lived with my ex-wife for 6 years and finances was never a problem because she handled the finances while both her and I worked to support each other--so that experience is something I think about when it comes to our future. Granted, she is taking an online course in order to be a vet istant, but I don't know how long that will take her. I've impressed in her the importance of having even a part-time job because what she brings home now is far from enough, plus she would need money to buy a used car, which is a ways out. So you can see why I'm worried. I've even had the thought of calling off the engagement indefinitely & break up with her because I just don't see the motivation in her to go out & earn some money. I figured I would give her about 3 months to find a job (when I gave her suggestions as to where to apply for PT jobs, she said that she wanted a PT job that she liked; this bothered me because I was the exact same way when I first started working--I told her that she just might have to swallow her pride and take what's out there, and that beggars can't be choosers, which she bristled at). I feel that 3 months is enough time for me to see if in fact she can find a PT job. I just want to know if I'm approaching this the right way or if I'm being just a little impatient. (Another note: she's volunteered at this shelter for 15 years, and in that time has had only 1 job which she didn't last long at.)