Oh boy.
The first one I EVER made was when I was in the first grade and it had to do with a time travelling cat that met dinosaurs or something. Sadly I no longer have it.
If we're talking the first comic I've ever serialized and shared on the internet it would be the majestic prototype to Redux which I ran from 2012 to 2014. It was... Ugly, and I was literally making it up as I went, but I learned a lot and my art grew quite a bit as a result. Also, I really fell in love with a lot of the concepts and characters, and swore I'd come back to it someday.
For a comparison, the evolution of the artwork was something like this. (Note, I usually put dialogue at the bottom of pages, kind of homestuck style.)


My current art in comparison is still a bit rough, but its come a long way.