Hi and welcome to the forum.
Under each of your posts you see the "Edit" and "Quote" buttons (also the "+" sign for multi quotes). While "Quote" lets you quote other users' posts to reply to them (the plus sign lets you select multiple posts to quote from across various posts/users) using the "Edit" button allows you to go back to _any_ of your posts and edit them.
So just "edit" your post to your own discretion - be it for typos, changing your mind, finding better wording etc. No prob!
You can edit your 1st post and delete your 2nd one as the 2nd post would be superfluous.