I watched Demon Slayer at like age 9 or 10, can’t remember, my siblings are younger than me though and they watched it as well (Both in the single digits)
We watched Attack on Titan and JJBA too but that was a couple months ago and because of my brother, who’s younger than my sister. My brother and I also read the Chainsaw Man manga he bought but I had to confiscate it from him because of volume three
I haven’t really gotten scared by any of that though, compared to when I was 8 and younger