This may be your first fic, but it had better not be your last! This is terrific, and it's hard to pick just one or two things to love about it; BUT, if I had to, one would be the way that Hogwarts herself befriends Severus when no one else can or will, and the way that she reveals painful secrets on par with those kept from Harry all this time.
The other would be this:
"it would be quite interesting to find out what he was like without the constant strain of conflicting allegiances, fear, duty, and pain. It would be something to discover."
This is, to me, one of the cruxes of good postwar Snarry - how does Severus change - evolve (or not) - once all these other burdens are no longer there? And I love how you couch it in 'discovery', tying it neatly to his aforementioned discovery of his cure and love of experimentation. Really well done, indeed. :)