Everytime I get close she pulls back

I have been talking with this girl for over a month now. She isn't ready to meet yet, but she is obviously excited and very interested in me. But it seems like as soon as I start to get very close to her heart she pulls back and goes quiet for a while. When she talks about the future it's like she keeps it vague, but yet she keeps our daily conversations like she is quite into me. To keep into perspective she has been through some trama and divorce, raising a kid by herself. She is honest with her struggles, and doesn't hide what she goes through. I'm a sucker for honesty lol But for my mental health, is there any female insight out there that could help me understand why she pulls away the closer I get to her and why she won't commit to actually see what we have in a physical sense?