The default for blog posts is to show in reverse chronological order, with the most recent posts appearing first. However you can override this by making some posts “sticky”, which you have done. This is why you see posts at the top of your homepage which appear to be out of date order.
You can go directly to a list of only your Sticky posts so that it is easier to edit them without going through all your posts. When you are on the Posts page in your Dashboard, that lists your posts, you will see small blue links for All – Published – Sticky. Just click on the link for Sticky.
You can then use the “Quick Edit” link (which appears when you hover your mouse over any post title) to get to the checkbox to un-sticky an individual post.