I think she probably knows Kara is Supergirl. I think they brought her in as a replacement for Maxwell Lord since he disappeared never to be mentioned again. So either she will become Kara's/ Supergirl's ally or enemy.
Maxwell Lord knew who Kara was and at first was trying to kill her but then started working with her to get rid of the evil aliens. I think that would have worked better going into season 2. Instead season 2 is a total mess with everyone being an alien or superhero and no one seeming to have any direction as to where things are going.

Lesbians are not around every corner in the series. You can count on super girl not being involved in any subplot having to do with this matter. To much of a hot potatoes.

She either knows Kara is Supergirl or shes in love with Kara.

I agree Tho I feel like she already knows Kara is supergirl

That would be overkill considering the big revelation about Linda Carter's character.