HP: Life in Hogwarts ( SI OC)

You know the drill, a college student woke up as 11 year old Callum Haven, he founds out he is in Harry Potter universe. Read as he traverse through magical society as a muggleborn orphan.
This fanfic will be a realistic approach based on the seven books and not on other fanfics and fan theories.
MC won't just get lucky and have special encounters like some other fics. For example, realistically there is no chance for an orphan to get a special core for wand other than the three that Ollivander sells, so don't expect MC to get a Nundu whisker core or any other special encounter like that.
If that is not your cup of tea, you can still try to read it for some chapters and then decide to drop it if you don't like.
MC will become friends with Golden trio but he won't be a part of it. And helping them in events doesn't mean that he is part of their group.
Pairings have not been decided yet. Romance will happen after fifth year at least and it will take a long time for that. It's not a priority right now.

This is my first Fanfic, after reading uncountable number of them. I would appreciate some constructive criticism as english is not my first language, so language in the story will be simple for London in 90's.

This story will be available on fanfiction. NET

I don't own Harry Potter universe, everything except the main character belongs to JK Rowling.