Is this a good thesis statement for an essay? If not, how should it be?

In To Kill a Mockingbird, the auther Harper Lee chooses the protagonist Scout to be the narraotr of her novel because she is young, innocent and the narration is written in her adult perspective.

It's fine.

Spelling -- "narrator"

Word choice -- "written from her adult perspective."

Yes, the given thesis statement is a good one, as it clearly states the author's decision to use Scout as the narrator in To Kill a Mockingbird and provides the reasons behind that choice. However, it can be further improved for clarity and precision. Here's a revised version:

"In To Kill a Mockingbird, Harper Lee employs Scout as the narrator, utilizing the duality of her perspective as both a young, innocent child and an adult reflecting on her experiences, to provide a nuanced depiction of the story's events."

This revision maintains the original thesis statement's main points while refining the language and ensuring clear expression.