I'm kind of close to having a golden age through excess happiness. My question is, will building the Taj Mahal reset my excess happiness pool to zero? Or will the happiness pool stay the same and the Taj Mahal golden age is just a bonus and I can get a happiness golden age soon after?

Thanks

Happiness pool will remain the same after the Taj Mahal golden age ends.

He's right. It picks up where you left off.

Cool. Thanks a lot guys.

Also, if you were already in a golden age then  had it built, the golden age would extend, same with sacrificing great people.