I think that's a fine plan, I'd just add one more thing.
Skull --> Planes --> Muscles --> Fat (skin) --> Face
Knowing how facial planes work is kinda like the forest, muscles are the trees. Going straight from skull to muscles might get you lost. I also recommend looking up how fat tissue works, that's why I changed skin to fat. Just thinking about skin will make you try to wrap the muscles, while fat tissue will sometimes do weird things, so you have to study both at the same time. Alternatively, you could start studying the face as soon as you master planes and use fat/skin/muscles studies to better understand what you're doing.