Loved it. I generally like de-aged Snape stories, and this one is excellent with the use of the memory loss. I love how he goes through his teenage years again, bigotry and all (nice that you didn't whitewash it), but begins to rethink his positions because he had someone talk to him like he mattered.
Snape wanting to shag Harry over the course of the story was funny, and the payoff was worth it.