Scuba isn't intuitive for me in-water, and I'm not athletic, so you may be much more a natural than I am.
Suck up all the head knowledge as quickly as you wish, but take the in-water progression slower. We don't know what we don't know. In-water, your brain is task loaded with buoyancy maintenance, diminished peripheral vision, lack of auditory situational awareness/directional hearing, operating in a 3D environment (rather than walking on a horizontal plane topside) and has gas supply remaining, current depth and perhaps NDL in the back of the mind.
It's a lot like a desktop computer with a browser with a bunch of tabs open, anti-virus software running, and more...and if you suddenly need to deal with an emergency situation, it can be like throwing a video render into the mix...your computer seemed to be running fine, the task is expected to be within its capabilities, and yet somehow it becomes the last straw.
There are things that sound like no big deal to conceptualize sitting here at my desk that can just about stall my brain out in-water, or tasks that sound like no big deal that I might be unable to do (like if you jump in, go down and realize your forgot to turn you air on; surely reaching back and over to turn your air valve shouldn't be too hard, right?).
And panic can blow a rational mind. It takes time to dive enough to have some screwups and surprises to get a sense of how you react to them, the good and the bad. The Accidents and Incidents section of SB makes for interesting reading.