Creation of the world

Hello, Your Honor.
Rabbi Eliezer's opinion is that man was created on Rosh Hashanah, and therefore he also concludes that the world was created on Elul 25 of the previous year. In other words, he subtracted six days. This means that he thought that the days of the creation of the world were days like ours of 24 hours (including the first few). Is that correct?
Is the view that the world was created on the 2nd of Elul literally the accepted one among Talmudic commentators/Rishonim/Achronim?
Isn't that a problem for the world being billions of years old?
Thank you very much.