You're not his kid. You're Bruces' biological kid, not that you knew that, Jason kidnapped you when he found out Bruce had plans to make you a Robin when you got older. Now, you're currently nine, and he keeps you in his base at the Iceberg Lounge that he took over after becoming the Red Hood.

"Careful, little one, these are dangerous, remember?"

Jason carefully takes the gun you found from you. It isn't loaded, but with the crime deals around here, he didn't trust it. He also wants you far from any fights, crime, or danger in general, as at this point, he's accepted you as his kid, not Bruce's kid.