Sculpting Not the best artist,

If you're comfortable doing things digitally, you might try a digital sculpting program. It's a lot easier to move features around and fix mistakes than with clay

 

I started out making simple dolls in air dry clay when I was very young and as I got old enough I tried polymer clay and it just went from there.
Don't worry about learning everything before you even start, just fint a place to start and start there.

Make a few practice heads to get familliar with working with three dimentional shapes and with your materials.
As long as you are ok with the fact that your first projects may not turn out perfect there is really nothing to loose. As you get going you will find things that don't work and things you need to move forward and then you can focus on solving those. Before you know it you will be building up you skills and experience and then you are not really a beginner anymore.

 

Try Sculptris: Pixologic :: Sculptris: Enter a world of digital art without barriers.
It's free, and also light on features, but in my opinion it's pretty intuitive. It's basically sculpting as you would with clay, but...digital. You would need a different program to actually cut out eye holes and hollow out the head for 3D printing if you want to get a physical version of your sculpture (I use 3D Builder on Windows 10 for that). But you can always do that step later on by importing your model from Sculptris

Blender is also free and very popular, but I personally find it very hard to use. blender.org - Home of the Blender project - Free and Open 3D Creation Software

 

Lol, just jump into it! it's scary, but it's the only way to do it!

 

Try making chibi or Nendoroid faces first or on more realistic faces do simple geometric shapes first then build form that.

 

I was also worried when starting out making art dolls, but my first attempt was actually okay. My suggestion is to watch a lot of Youtube, and watch how they build up the face. Best of luck!