First, you have to understand that a girl flirting can mean a number of things: it could be that she likes you, or it could just be that she has a flirtatious nature, so in her eyes it’s all innocent play. Now, she said five weeks ago that “she didn’t think she could handle a boyfriend right now.” There may (or may not) have been something going on in her life at that time that you may have been unaware of, but either way she saw a relationship as an added stress. Things may or may not have changed within that five weeks. I think communication is the key. I’m assuming that you guys are friends, and as such, you should discreetly pull up a conversation to see where she stands on being in a relationship, and the rational behind it. Knowing where she stand will aid you in what to do next.
She may in fact like you, or she may just see you in the context of being a friend right now, so I wouldn’t come on too strong right away. If she would consider being in a relationship, you should be genuine and express the way that you feel about her, and ask her out. Don’t rush to the being my “girlfriend.” Date first. If she doesn’t want to be in a relationship, you have to respect her and her feelings, but that doesn’t mean that there is no hope. You could take the risk and still tell her how you feel. Here is the thing with that, you tell her so that she knows how you feel, but not to force her into a relationship. With the risk, you also have to be open to rejection. But, it is good because it tells you to move on. Let her know that you care about her, and that you are willing to respect her, and stand by her. Or, you don’t take the risk, and spend the time trying to make her see that you are good together. Personally speaking, I would take the risk because it gives a definite stance on both ends, and when she is ready for a relationship, she knows how you feel already.