So I was flying my spark today and it gave me the low battery warning and was going to auto land, I tried pressing the cancel button and tired pressing the red x but it didn’t work and continued to drop. Is there a reason why it wouldn’t let me do that? I feel like it should.

Hello and good day Jere_Ana. Thank you for reaching out and for the inquiry. When the DJI intelligent flight battery level is critically low, the DJI Spark will automatically land, and the operation cannot be canceled. The only thing you can do is make sure your drone is back home before the battery is deemed critically low. Have a safe and happy flying always.

Hello there!!It is not possible to cancel the critical low battery auto land. However, you can still control the drone with the RC sticks (move forward, backward, right, left, turn) as it descends. You can even gain height (only to some extent I believe) and make sure your drone is landing at a safe location.

Yes , in case it was a critical battery autoland, you can't stop that.
You can however keep it in the air with active throttle up, just it is in need to land quickly!
In "best case", the bird is on low altitude and close buy, so this is "just" a battery life saver, starting at 9%
In bad cases, you are still high(er) in the air (and perhaps a bit further away, b/c of canceling the/one  batt RTH "bird is going home in 10 secs" , at around 20%), you have to think about: critical here has also to do with height.
The critical battery landing can already start at 14, 18, ... %, depending how high you still are.
The bird always trys to get you down, so that you not fly to long around , under 10% battery life.

You can not only throttle up but also use other stick commands so that if you're over water or rocky terrain you can move it to a safer landing zone.  You just can't cancel the auto land as you asked.