AITAH for locking the door on my brother?

Hey y'all! So basically it was 12 am and my dog was barking at the door for a solid ten minutes and so I locked it because I started to get scared. I looked outside for a second and saw some kids riding bikes so I thought it was just them. My brother ended his shift at 9 am and so I didn't know he still wasn't home yet and found out it was my brother who was pulling in on the side of the house. He was only locked outside for a minute (when he got to the door) and I opened it immediately when I realized that's who my dog was barking at. My mom went ballistic and started screaming at me at the top of her lungs for locking my brother out and trying to purposely kill him. (We live in a really safe suburban neighborhood). I was yelled out for a long time and called really harsh names, but I tried to tell them I didn't know my brother wasn't home and it was not my intention to lock him out.

So redditors, AITAH for locking my brother outside?