It's been a few years since I read it so I am fuzzy on the details of the plot but this is what I remember...

The protagonist is a female cultivator who is the enemy of the male lead and is killed by him in the first few chapters. She reincarnates with her memories intact and swears revenge on him. The male lead also dies for some reason and reincarnates but loses his memories. She becomes the elder (?) of some cultivation sect though she still has the body of a little girl. Through some wacky events, the male lead becomes her disciple and falls in love/gets obsessed with her.

There were also some vague hints about the protagonist being isekai'd into the cultivation universe, but I hadn't read that far ahead.

It had over 170 chapters when I last read it.

Hobbies include impersonating fictional characters and sucking on ketchup packets.

Meng Shi Zai Shang!