Yes, you can edit any posts you've made in the past.
There are a couple of ways that you can edit, or delete posts from your page.
1st way: You can navigate to the post icon on the left-hand side of the page. From there, you can go to Published page of your Post section to view all of your published posts in one place and choose which one you want to edit.
Find the post you'd like to make edits to, or want to delete.
2nd way: You can also click the pencil icon at the bottom of any post on your creator page.
You'll be able to edit/delete your posts from there.