how hard is it to code neji and how long do they take
at your current level, about 3 months to get the very basics.
then you can program a bit more than a "hello world" program.
(a program that outputs "hello world" and then terminates)
I might be a special case, but I started to program at the age of 6, though tiny things, I got familiar with programming. (C64 with Basic). With 13 I got a school computer course, and had a friend who was very into programming, he dragged me in. With 15 I programmed graphical simulations like bacteria popuplations on a sample probe "fighting" against each other, along with mutations that caused new bacteria to enter. (I still have that program)
That was when I wrote in PowerBasic & Pascal.
At the University I was teached now Java and C, PHP is somewhat similar to C, so it was a good course of action.
As for LotGD programming (PHP is vital, but Lotgd uses many own functions you need to know) I am now into it for 1,5 years about. I invested a couple of hundreds of hours I guess.
So expect results on "shinobi legends accepts this module" basis not before 12 months. (rough estimate, you also have other duties and you might be faster or slower a learner)