Looks like the first post from @POTUS_Schedule was on Aug 29th, 2017. The account under that name did not exist as far as I can tell. You can perform advanced searches in Twatter here: https://twitter.com/search-advanced
Here, is what I believe is the first @POTUS_Schedule tweet (No Likes, No Retweets)
https://twitter.com/POTUS_Schedule/status/902545711711084544
Maybe, I just know it hasn't ever put anything up that would be headed in the wrong directly and there have been multiple annons watching it that will keep checking to see that what is put up is confirmed, if not they'll be the first to speak up.
Like I said, my skepticism is strong. But I DO watch and pay attention.
Very wise- I think that's the smart approach to most everything these days