Honestly, I would top it off first to see if it improves performance. Get more miles out of it and then change it next year.
If you use the fluid JD sells you, it will be very expensive to change the fluid and then find out the hrydro pistons were worn.
Don't tell my mechanic friends. I have never changed the transmission fluid on my 2003 F150, 140k miles. Have had it since new. Shifts fine. I had to top fluid off once because the dipstick tube rusted and broke off the bracket. Would leak when I turned corners. I welded it back together and has been fine since.