Hi randomguy73. It sounds to me like she just wants her space. You're right, without context it's hard to tell why, but if you've made it clear how you feel about her, all you can really do is give her the space she needs and let it go.
By 'made it clear' I mean, yes, your actions may indicate that you care, but have you ever said out loud, I still really care about you and would love to see us back together at some point? Or something along those lines. I think if you make a clear statement of intent, and then go by her reaction, you can't go wrong. It sounds like she's being evasive, for whatever reason, and by saying that she's the type to be quiet when she doesn't know what to say, it sounds like she just might be awkward in intimate situations. Which is fine, no judgements, but I think that you also need to protect yourself. You don't actually know what she's doing with her life and if she wants you in it on a regular basis. And if you are super attached right now and just kind of hanging on waiting for a sign that may never come, it could explode in your face.
So, express that you care and want to be there for her, and ask her what she wants and needs. And then go from there. Decide whether or not you can live with the response/request. Good luck.