I think if she doesn't really acknowlege the dinner in a positive way (as she may have had a lot of conflicting emotions too, and got scared) the next timee you see her "going cold" you should back off and not go.
Depends on what type of person she was--did she do things half-hearted and then have "good memories" later? or if she was pushed to do things she didn't want to do, did she have negative memories later.
Going dark means just that--you don't really come out of it much if at all. It seemed to have worked well for you, but then you came out pretty quickly to accomodate her.
Don't jump at every invitation. If you do go, be "distracted" when it comes to her--answer some texts and have a mysterious air. Let her be curious what you are up to.
