I have no idea what type 3c/4a hair is but whatever your hair it will eventually lock up naturally and seeing as youre african american Im guessing you have the type of hair that will lock up pretty fast.
I would definately recommend going natural. You said yourself you dont want them even or neat or anything like that so why bother tnr? I initially done tnr but felt like I was cheating and missing out on part of the journey so I decided to take them out and start over. My hair is probably the complete opposite to yours (its very straight, fine and now about 5 inches), it used to never get brushed yet I never got knots. After changing a few little things like the way I washed and dried my hair and sleeping on a wool pillow Im getting knots already and Im only like just over a week in from going natural. If my hairtype can do that imagine what yours will do.
Its totally your decision though but I personally would say go natural. Hope you have an amazing journey.