Tbh, the fact they have a past, for me, means that most likely things will only work out after he remembers her. I was frustrated when he wasnt curious or shameless enough to look in her box, but i suppose with her knowing him completely she knew he wouldnt.
But is really mysterious to why she wouldnt mention. Is clear he dont remember since shes exactly a bigger version from the photo. Anyway... lets see how it goes.