Okay, so I've been writing this fiction of mine and I have this two characters whose names I have trouble with. One girl is named Ivannah and tho other one is named Marrilyn (MC). Everyone in the story calls Ivannah Ivy and Marrilyn Marril, except for teachers and sometimes their parents (parents and teachers are not much in the story). My problem is that I dunno if I should call them how everyone else calls them while writing, or should I always write their real names. Because their real names don't appear that much, while nicknames are regular. I just need your opinion: do you like it better when the characters are always mentioned by the author by their nickname or by their full name? I like both and I can't make up my mind so I'd like other people's opinions about it. It might help me decide.