Karen, The new DNA confirmation page was added a couple of days ago. I'm not sure when it will be officially announced. The wording that you suggested is fine, but it in order to be consistent with the new instructions, it should also have a statement in this format: Estimated number of generations to MRCA = ___, based on sharing 3585.1 cM across ____ segments. (with those blanks filled in) For most statements you will also need to name the MRCA and each test takers' relationships to the MRCA(s). With a parent/child relationship, the MRCA and relationship are obvious and don't need to be restated.
To answer your other question, yes you should rewrite your previous DNA confirmation statements. Because of the European Union's GDPR, you may find that some of your statements in the old format disclose non-public personal information for living people who no longer have their information displayed on their WikiTree profile. And there's additional information that should now be included in each confirmation statement.
If you're having difficulty understanding the new instructions, please let me know your questions and I'll be glad to help.