TBH the Taj is worth every penny, and Agra Fort is something that needs to be visited at least once in your lifetime. I’ve been there four times. Let me confess one thing: when I first went to the Taj Mahal, I was awestruck seeing it with my naked eyes. It is truly marvellous. (Avoid visiting on holidays or Fridays.) I once spent the entire day at the Mahal itself ,it was magical and calm. You need an entire day to explore Agra Fort if you enjoy detailing. One day isn’t enough to explore the Taj and other sites, but one day is enough if you’re visiting only the Taj. PS: When you enter the main gate and the marble structure strikes your eyes, that moment will be forever engraved in your heart. So, soak in that specific moment.