Can we all come back to earth? I'm not ruling out an Iron Maiden album being recorded in 2019, but it would certainly be after the next leg of the Legacy of the Beast World Tour. I think LOTB is likely to stretch into 2020, with a short European leg with an altered setlist, much like Maiden England. That might be where we get our one new song, in 2020. That's the absolute earliest I think anyone can expect a new track from Iron Maiden.
Every time people on this forum get themselves worked up over these little tidbits and rumours they walk away disappointed. How many of you were completely sure this was the tour where AtG was going to be played? How many people were sure we were getting a new album in 2014 for the last leg of Maiden England? Going back, I remember intense speculation on an Iron Maiden album coming out in 2008.
Don't get your hopes up. Iron Maiden is a huge enterprise, and this band does one thing at a time almost all of the time.