And the end of the day, Sarada will be a pairing fodder for Boruto. Much like Sakura to Sasuke and Hinata to Naruto.
Kushina loudly said she was going to become Hokage, but her husband made it.
In Kishi's world, it's always male > female. So go figure.
As long as Boruto doesn't change his mind of not wanting to become Hokage, Sarada has the chance.
But if suddenly at the end of Boruto movie he declares "I want to become Hokage", Sarada's chance will reduce to 0%.
"Who can challenge Sarada?" - the real question is "Who can challenge Boruto the prodigy of the new gen?"