I went straight from a 20 inch to my 36 inch, and the learning curve for me was a matter of minutes; in less than an hour I was able to mount sucessfully about 80-90% of the time. Good luck!
The learning curve for me was not long, but I came from a 29er: a few minutes for the mounting, an hour to get comfortable riding easy off-road.
I have two tips for you:
Use the longest cranks you can get to start with, preferably 170’s. That way you will sit lower, have more torque and control, and is way easier to mount. After a short period of time you will get used to the 36er and you can put the original 150/125 cranks back on.
If you want an idea how it feels to mount the 36 er, place your 24" on something that is 5 to 6" higher than your feet and try to mount it. Do that with short cranks (<125 mm).
This will feel like mounting a 36er with 170 mm cranks, height wise and torque wise. The only difference now is the wheel weight.
I think you’ll notice that you’re smiling.
Getting freemounts consistent on the 36 was the hardest part for me. But that said, I managed to get 10 successful freemounts within a couple hours of first getting on the 36 (out of maybe a hundred tries ).
The 36 really opens up possibilities of actually going for rides on bikes paths etc.
Get one!