You should learn to draw while making a game imho.
Even if it is another one for the sake of learning while making something simple, you learn to draw and get more comfortable with ren'py, it is a win-win.
Take a look at:
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my old project and then compare it with the latest CG of the same game or to my recent one (signature), while I did not become an artist I think it is decent enough for a game.
-edit-
Faster comparison: I released the first version of Sexymon Adventures on 27 September 2018 and the ass in my signature on 1st November 2018, that is roughly ~1 month progress.
If you draw with a purpose it will feel nicer and you will improve faster.
Not saying you will not improve otherwise but you will surely have more motivation.