If you want to create your own theme to use on sites I suggest using a blank theme like Bones or _s (underscores) or even BlankSlate

Then you do not need a child theme. You just name the theme for your website and start creating.

The main reason to start with a blank theme is they usually only include some basic functions.

The theme I use for all of my websites was created from Bones but has been customized so much over the years of use and updating that it is pretty much completely from scratch now. I have a Bootstrap 3 and 4 version with many custom options and features.

I always start with underscores.