I don't think saying to Lostsoul 'you should have banged her by now' over and over is productive for him. It may be hitting the target, but it doesn't explain why or what is going on at all. Lostsoul, I think what the real issue is, is that the age difference is playing too big a factor for her mind, and that it seems like you're doing the pursuing, when it should be her seducing you, fully. You may be truly interested in her, age and all, and she may like you - but the way you're approaching it is more 'conventional' (I'll say it that way).
When you're hitting her up, and pushing the interactions, I think she is taken aback by the sub-conscious fact that a 28 year old is pursuing a much older woman, 37 years, for a relationship. That alone plays a major role, and puts doubt in her mind about you (not even going into the whole 'guy should never chase/girl should pursue'). It's like an extra layer that needs to be added because of the age difference.
If you were pursuing her for sex, she could more appreciate that as normal male behavior, and be more relaxed about the finer 'relationship' details. OR - the best way, is to be aloof about the whole thing, and let her make all the moves. She NEEDS to seduce you, in order to feel normal about the exchange.
I'll tell you a short story. One of my friends is in a 'relationship' with a woman much older than him. He lives his own life. But they started hanging out as friends, hanging out literally all the time. Then I'm sure something happened when they were alone. And it gravitated from there, to even living together. They're ok together, not great. Lots of jealously from her, fights here and there. Not something I'd recommend at all. But the key is, he never seemed to 'need' her, he was always 'whatever' and was very willing to walk away, not give in to the little fights here and there. I'm certain that she charmed him slowly, and he was very comfortable in being placated. I will say though, they will never have a normal relationship, as in fully comfortable, because you just know that that person is not age compatible. And what if it works out? One person will die much sooner than the other. And no kids to boot.
So my advice to you now, is to back the hell off, be pleasant to whatever communication she puts out there, and let her do absolutely everything. Be seduced by her, and if she doesn't seem to want to get closer emotionally to you (it's the girl way) or sexually, then abandon ship. Or use her for just friends even. Go ghost on her, and if she does come back, then that's your answer, if you choose to go with it. If she doesn't - guess she wasn't that interested.
I don't recommend it though, even if you're lonely for company. Easier to eject with little attachment than much more.