Is Walden by Henry David Thoreau a good book?

It was high school reading when I was you age, so it's not too advanced. Give it a try if you want to.

I read it, or most of it, anyway. Seems I remember thinking that it would have benefited from a good editor.

If you want to read Thoreau, maybe start with a shorter work, like "On the Duty of Civil Disobedience".

(Both are out of copyright, and available for free on sites like "Project Gutenberg" and "Open Culture".)

Some people think it's good, some do not. You're not going to get one correct answer on a viewpoint question.

It's been around for a long time for good reason. Just give it a try.

Get the book from the library and read it until you either decide it's not for you and stop, or you finish it. There is no rule that says you have to finish a book once you've started it, come what may, and no one here who knows you well enough (or at all) to be able to tell if you would like it.