My T and I go over an hour often, as I'm usually the last patient of the day, which I love. I feel like there is no pressure on us. Sometimes its an hour and a half. But we have had a few 2 hour sessions unintended.
We just kept talking and things kept flowing.

Dont focus on the time. It will probably fly by and having this extra time
will help you to really breath deep and calm yourself as you go through this process. Savor it...dont sweat it. Good luck!