Sakura already realized that a long time ago in manga canon.

And another point, it's already been stated that Tobi Madara creates the genjutsu characters personalities, not Naruto and Sakura, the only characters that aren't created by Madara are Minato and Kushina- my guess it will turn out to be some seal created by Minato and Kushina to protect Naruto when he's in grave danger- a variant of manga canon.
Madara would be basing the flipped Sasuke's personality based on the images in Naruto's, Sasuke's and Sakura's minds from their 12-13 year old interactions, not the current feelings, and more than likely he gets little to none from Sakura- Kishimoto has shown Sakura by 13 could naturally see through and had some resistance to genjutsu - It appears even from Itachi's in part 2. So it would be almost all from Naruto and Sasuke's minds, and their perceptions of what Sakura wanted at age 12-13. It's not what 16-17 year old Sakura wants at all (as is very obvious in part 2 of the manga), but it still throws her off, thus the embarrassed blush (it's likely close enough to her silly naive 12 year old fantasy, much to her mature self's embarrassment), but even more so she's tense and freaking out- she is embarrassed by the memory, but is freaking out to see it come to life of a sort and she knows they are in a genjutsu and is very tense. It throws off her mind just enough to distract her from trying to figure out how to break the genjutsu with Naruto.