Alright so I'm not exactly used to writing critique [so please excuse me a little bit] but here it goes:

The overall idea of this is excellent. It's cute, and very easy to love. However there are a few things I notice that could use a bit of work.

Now you've probably already heard this from another person but the first thing that keeps sticking out to me is the way she's sitting. It would look better if she's either higher up on the tree [meaning so it didn't look like she's magically stuck on the tree] or her head is facing upward [if the view is from the sky then it would look better and she would instead be sitting on the end of the branch instead of on the side].

The size of the branch. I'm probably that much of a city girl but I don't think there are an tree with branches that big. Especially if the branch is high up [normally it would be getting thinner higher up on the tree].

I'm not really sure if I like the background with all the leaves and such. I'm used to seeing a blue sky but that's just me.

Other then that I love the coloring and the way you drew it. Those few things are the only problems I see.