This is a great starter anime
The series is all about friendship and how caring about someone can change their life dramatically. All of the characters deal with things that are traumatic in their past (like the main character losing her mother) and are uplifted by the friendships around them.
There is some flirty interaction, but none of it is adult in nature. Also several characters are cursed to turn into animals when someone hugs them, and when they turn back, they are naked and have to put their clothes back on. There is no nudity, and it is always handled in a comical way that is non-threatening.
It ends in a very positive way, with a great message that kids in this age range should be able to understand and appreciate.