After seeing this scene again, I think Daenerys will probably give up the Iron Throne to help Jon Snow defeat the White Walkers and she will probably die in that war.
But I do believe she will actually defeat Cercei, she just won't have time to start ruling the seven kingdoms. Also, according to Cercei's prophesy:
"Until there comes another, younger and more beautiful, to cast you down and take all that you hold dear."
This is most likely Daenerys, I don't see Sansa nor Arya being capable of doing that. I think Danny will take the last two things Cercei loves the most, power and Jaime. Dany will probably kill Jaime or he will betray Cercei by joining up with Tyrion and Dany.
What I really don't want to see is Dany losing to Cercei in any shape or form. If Danny dies or loses her army, it should be in the war against the White Walkers, not against someone who is bound to lose because of her stupid decisions.