Transmission not shifting in from first gear?

This sounds like the input shaft speed sensor is not working, can I ask if you have check engine light on? If so, let's run the codes to help confirm the sensor failure.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Here is the sensor location in case a code comes up for it. Also, I would check the fluid condition to make sure it is not burnt. Check out the images (below). Please let us know what happens.