Is eternity just an idea?

Eternity is the only thing that seems to answer alot of questions, but eternity could just be an idea. What if there is no such thing as eternity?

ie;

Lets assume the world had a point of origin. We would then assume that there couldn’t have been ‘‘something’’ before because that then means that that isn’t really the point of origin. When you think of cause and ffect then there can be no first cause right?