Welcome to the boards

I'm gonna start from the bottom and work my way up from there:
The feet feel off to me for a couple of reasons. First, they're both flat on the ground plane, which doesn't really look natural, but also because of the way they're pointed. She's more or less facing towards us, yet the foot directly under her is a side view, which is hard to do if you try doing it yourself. Here's an edit to show what I mean:

Personally, I think that feels a bit better. Not the best edit in the world, but you get the idea.
From the waist up she looks pretty good. The hands could use some work. It looks like she's wearing mittens and her hands are kinda small. I like her face and the head, but you can see the scyth behind her head, and that should be covered by hair. The blade on the scyth is also a side-view sort of thing, and if she were holding it to the side like that it would be going THROUGH her head, not behind it. The coat looks good until it gets down to the waist and the legs and then it keeps spreading out. It'd look more natural if it fell more vertically down, and maybe if it draped around her instead of flattening into a triangular shape. There's a hint of a curve on the left side (our left), but it still feels very flat.
The pole on the scyth doesn't look like it would support that much weight, but I figure that's just a stand-in or something. If it's not, then you'll probably want to give that some more weight, and maybe make it more than just a straight line.
I won't really comment on the pixeling work, since I'm also pretty new at it and I've not got a great handle on that aspect yet, but there are some red pixels at the top of both legs that don't seem to add much.
Anyway, you mentioned that you didn't use any reference, and i'd say that you probably should. Not pixel art reference, but photographic. Look at photos of people in a similar pose, or grab a mirror and be your own model. Best way to learn how to draw, paint or pixel something is to look at what it is you're trying to replicate.