Hi Chaslan 45, I would say that the theory will make you a better player, but you have to become a player at the same time as learning the theory. Make sure you are picking up your guitar most days. With your chord changing take it slowly and develop the motor pathways between your brain and fingers. You have to slow down to speed up, as my old guitar teacher used to say.
As for your pinky, I read a while ago about a guitar player who had only three fingers on his fretting hand and could play very well, so I guess where there is a will there is a way!
Tom N.