Your edit, seen [[1]] was reverted to the previous edition. The edit was in good faith, though the change in grammar can be argued to be proper or improper. That is up to the admins to decide.
Don't let it beat you down. We've all experienced it in one way or another in editing, having our work undone. Editing is just a matter of finding something that is genuinely wrong with a page's content (such as spelling errors, grammar mistakes, mechanic failures, or false or misleading information) and correcting it. Edits will be reviewed by the administrators or rollbacks and changes that are deemed appropriate for the page will be kept.