This is Morta (my OC and the protagonist of my forthcoming kids' scifi novel) aged seven, about four years before the events of the first chapter, with one of her best friends, Ciarán NacNair, who is about a year and half older than her.
They have just beaten the living snot out of each other, but don't worry it was only a playfight. They always make sure to do this out of school hours, and away from school grounds, as teachers tend to become confused into thinking their fights to be something other than simple good-natured roughhousing. They also make sure, after a fight, to take time to sit and chat, help each other with any first aid they may need, and wind down from the adrenaline together, to assure each other that no ill-will was meant, and they are still BFFs.
In general, Ciarán is a pretty gentle, thoughtful, conscientious kid, interested in philosophy and theatre, and not normally prone to brawling after school. It's Morta who's the troublemaker - she's the bad influence here. Ciarán's mum does not approve of their friendship.