She struggles with her feelings for MC for quite some time, to the point where she said he is the man she loves, the one who make her feel warm, safe and the most important, but he is her nephew. So, she struggles a lot with all of this because for her, it's so wrong and gross but still loves him.
She technically not playing hard to get, it's just really difficult for her. Just remember the scene of her first kiss, she was feeling amazing, it was just one kiss but for her it was the most amazing thing, but getting intimate? With her trauma and all that, is already really difficult, add to that the fact that she's his aunt, for her it's just a no-no.
I won't be surprised if we see a scene in the future where Amy need to get drunk to get it out of her system, just talking about how all this makes no sense at all for her, but MC will tell here that love is love and like Liz, he loves her and he just wants to make her happy because she actually is his first crush/love and he is the man he is basically thanks to her (and Nana and Aunt Liz too). If he is so confortable with women and able to help them and listen to them is a huge thanks to Aunt Amy.
(Every time I think of her, I think of the friends who looked like her and I just love Amy more!
)