Until this point, I'd been pretty sure that Ayako was aware of Akira's feelings for her and was fencing them away, but she seems genuinely flat-footed here.
Reckon that's more because she's (not unreasonably) currently entirely absorbed in her own worries and absolutely didn't expect Akira to spring that on her.
From what we've been shown Akira's clearly been in love with Ayako for years. Akira picked up on that early, that's why she sees her as a rival/threat. I definitely feel like this is a last-ditch play to see if she has a shot, rather than just her "playing cupid".
You mean Asuka in the second sentence, but anyway. Akira hasn't exactly kept her interest in Ayako a secret and the flirt-reject routine seems to be something of a long-running joke between the two of them. But recall, if you will, that Akira also studiously and consistently avoids making serious moves on her in-law due to as yet still unspecified feelings of guilt regarding Atsushi's death (whether that is plain old survivor's guilt or something more dramatic remains to be seen) which Ayako is aware of and, irrespective of her lack of reciprocal romantic interest, appears to consider quite unwarranted self-flagellation.
Which would be one more reason Akira's surprise power move catches her so off guard here, and a major reason why I think she's going for shock therapy rather than "last-ditch play" - there's been no sign that we've been shown of Akira suddenly ditching that emotional cross she's burdened herself with for the past one and half decades.