Clearly an improvement!

awww a cute baby picture.

This not only shows how your art has improved over the last three years but it also shows how digital art software has changed, too. When digital art software was first developed, feathering (as can be seen in the new Sara drawing) was difficult to do, at best, and impossible, at worst.

Well when I drew the old version I had drawn it on paper, scanned it in and then I adjusted the contrast to make the lines darker and the whites whiter. Then more or less just filled the spaces and made some things with a mouse (I didn't have a tablet yet) in GIMP. I more or less used that technique for a short time until I got a tablet but even then I was still scanning images and then basically redrawing them on top of the scan for quite some time.
In May 2017 I made the switch to drawing everything completely digitally like I do now with a Wacom tablet, but still the same version of GIMP.

I'll take your word for it. I know next to nothing about art and less about digital art.