The raising of the Mary Rose, watched when Mum was resting in bed while pregnant with the older of my two sisters. Checking Wikipedia for the actual date, it was only a few days before Mum delivered too.
After that, it was an episode of Star Trek, Return of the Archons.
I got a weird ones.
Hitchcock’s Psycho. I have no idea I was watching this movie with Mom and my older sister, but I was. I specifically remember the shower scene, more for the sound effects than the blood.
One of my earliest memories is seeing the head bounce down the staircase in Hush, Hush Sweet Charlotte. I am sure i watched more age appropriate TV when I was young, my these are my earliest memories.