I think the important thing is that you are totally honest with her. Let her make her own decisions and go from there. I say this because I once dated a guy that was 9 years younger than me and at the time he had a part time job, no car, lived with his parents. It just so happens that he was emotionally able to give me what I needed when it seemed like nobody else could, so I chose to overlook those things. It didn't work out in the long run for other reasons, but he is still one of my closest friends, and I consider him to be one of the few people in my life that really does care about me.