When you're 10 years old you can't legally drink, smoke, vote, get married or even buy a pet. You're in year five or six at primary school. You're legally a child.
But you can be put on trial as an adult for murder.
That's because in England and Wales, 10 is the minimum age of criminal responsibility - meaning a 10-year-old accused of killing someone can be tried like an adult in a Crown Court in front of a jury, rather than in the youth courts.
A few concessions are made based on their young age, including their first name being used, lawyers not having to wear wigs and gowns, and being allowed to sit close to their lawyer or an appropriate adult.
But can a child that young understand what it means to commit a murder? Are they responsible for their actions? And what happens to them later in life if you convict them as an adult before they even become a teenager?
Those questions are at the heart of 12-year-old Ray's story, which is told in new BBC drama Responsible Child - loosely based on a real-life case.
Ray, who loves playing video games, learning about space and watching reality shows, is on trial - alongside his big brother, Nathan, 21 - for a brutal murder.
After their abusive step-dad narrowly escapes prison for attacking Nathan with an axe, he returns to the overcrowded family home and starts being abusive to their mum. One night, the brothers go downstairs and stab him more than 60 times while he sleeps on the sofa.
It's an attack so frenzied they almost cut his head off.
The story is based on that of Jerome and Joshua Ellis, who were 14 and 23 when they also killed their step-dad.