Personally I think it's better if you do not read the book because it doesn't make any difference in the real timeline expect teaching Scorpio and Albus be to be more active and also it is far off from the characters we know they seem to change like Cedric who was such a pure soul but somehow became a death eater because of some humilation and the time traveling was really odd as it implies whatever time and emotion we have spent on the series can be changed with next to no effort. So disappointed I never thought J.k Rowling would ever create such an unappealing work.