For Optimal Viewing and best picture from a 65 inch TV you should sit between 6 feet to 8.3 Feet away from the 65 inch TV.
If possible and you have enough room sitting further back as in 13 feet from the 65 inch TV will give you an even better viewing experience from the 65 inch TV.
But sitting 6 feet to 8 feet is okay when watching a 65 inch TV.