I must commend you for your superb writing. The way you described feelings, the gestures and the expressions is just amazing.
I wonder what's going on in Snape's mind. Is he having similar reactions and feelings toward Hermione as she does toward him? She's been observing Snape closely. I noticed not only does she bite her lower lip but picks her nails when she's nervous. Not too difficult to read her if she does that, is it? :)
I felt sorry for Hermione and Parvati when Harry and the rest of DA assumed it was Hermione who produced the Reducto spell. Hermione tried so many times to explain and then when she did it I felt like screaming at them. The expectations of all are so high as far as Hermione Granger is concerned -and for a good reason- but at the same time it puts a lot of pressure on her and she is already doing that to herself without her friends adding to it.
I do have my reservations about this pairing (Snape/Hermione). Aside from the age difference I find it hard to accept that a young, vivacious and rather optimistic woman like Hermione would find Severus Snape fascinating and/or attractive. He was a mean and at times abusive teacher who obviously hated teaching, at least that's the impression he gave me in the books. Hermione was/is one of his victims and her sense of justice would reject such treatment. On the other hand she might want and seek an explanation for his behaviour and after learning of his past Hermione would be willing to give him the benefit of the doubt. I also think Hermione wouldn't allow his constant puts down go uncheckered for long. She is very young right now but as she matures and becomes more confident there's no way the Hermione I admire would let anyone treat her the way Snape did and does.
I like what you're doing so far. No rush. It is a joy reading this story because of the great talent you have.