Weird shift on cold start

So I have read on the forum about having a “launching” feel when first taking off on a cold start but I’ve noticed that when I shift to drive there is a hesitation when I try to roll forward and hit the gas. Feels like it has to build up some RPMs before it goes. Tonight when I put it in drive and pressed the gas I had to do it a little further then I felt it shift and then started moving forward. This doesn’t feel like the “launch” forward feeling. Low ATF fluid maybe ? I just bought this truck used at 14,273 miles and now I have 14,779. From dealership. Any ideas ? Thanks in advance.

 

Low ATF... like most of the 3 rd gens..!!

 

Let it warm up longer and it won’t do it

 

Meaning... the fluid is now warm and has expanded Fill the tranny up..!! It's 1.25 quarts low... garan..F'n..teed..!!