Depends on the country and culture as far as I understand. I live in Brazil and here most people will only be boyfriend-girlfriend if it happens an official ask. Before that people can go out, kiss, have sex, but they will probably not consider themselves boyfriend-girlfriend and chances are it...
well I don't think having a key to a friend's house would hurt your reputation in any way? Maybe cause misunderstandings and MC would be shy, but only that lmao
That said, they were childhood friends. It's normal that you grow apart but when you interact you feel that sense of ease of being...