I think I have traumatized my little sister
How did you traumatize your little sister?
I've been loudly singing a song that has dirty lyrics to her.
You shouldn't sing dirty lyrics to a child. The child won't understand and will be upset.
Hey it's just a kid, no need to get all tinfoil hat.
It's the truth. This is why she is upset so you should watch what you say around her from now on.