I thought she loves her mother, but seems not so much)
I say Asuka is romantically and sexually in love with her mother. But as the flashbacks indicate, she's also a youngster with raging hormones and confusion. And so, it's not surprising or even disappointing (for me, at least) to see her getting it on with someone her age and someone not her kin.
I think it'll be super important to have the senpai as Asuka's "first".