Sexuality
Sora is bisexual with a slight preference towards girls. She didn't notice she liked girls as well for sometime because it wasn't like she didn't like boys and liking girls is considered strange right? She assumed her feelings towards girls were completely normal.
It wasn't really until she developed a full-fledged crush on Mimi that she realized that she also liked girls.
She's very private about her sexuality though and it's a very private matter to her, she hasn't told any of her friends (although Hikari found out but promised to not tell) and she has no intentions to tell her mom ever.
She hopes that she'll fall in love with a boy so that she never has to hide a relationship (she wouldn't want to do that to her partner) but she's realizing more and more with time that while she might fall for a boy, there are also high chances of her falling for a girl.
She's a little afraid of falling for anyone because of this.