If it needs that much work,you could put it under unfinished hidden.That way you can work on it without people seeing the progress.

It's fine, add a few more petals, make them curl around the inner petals and have the last few petals snung under the rest, like a real rose. The stem is far too thick, thin it out, almost the thickness of a pencil. Since the sun is on the left the right side of the stem wil be shaded, and the tree should be taller, right now it looks the same hight as the rose and it's making the rose look gigantic. Lighten the sun, blend the light green a bit more into the darkgreen grass, shade the right side of the trunk, and lighten the cloud a bit by erasing some of it (on low low opacity) Just shade a bit of the leaves and there ya go. I hope you don't take this in a bad way WMG, you are coming along in your art, this is advice. Keep it up.

the leaves look better, but the whole picture still looks wierd

I'd say yes. In the future make the rose smaller, nearer the bottom, or to set of the size put the tree farther back. But you did good on the tree, and the rose stands out better. The stem is still a little thick but much much improved. I hope your grandma liked it.