For your first painting, it's good. It does, however, look amateur (which is okay! Because it is!). Keep practicing and you'll get lots better. I would stick with acrylics for right now if I were you. Oils can be tricky (not to mention expensive). I would master one media before moving on to the next. I'd start on canvas board, then work your way to canvas.. but that's just me, I found it easier. Canvas reeeeally soaks up the paint and changes the way colors blend (which is good, once you're more experienced). Sorry, you said be honest! It's not bad though.
As for etsy, tons of my friends use it. It's reputable and safe.