I like this drawing. And I like using mechanical pencils for drawing too. There is something about the needle thin tip that makes me feel like I have more control. Plus there is no starting and stoping to sharpen your pencil.
About the pic size. I don't know if you have gotten an answer about it some where else, but if you want some advise, I'd be happy to give it.
The full view is awful large. Full views are meant to give a person a good look at the drawing, but it's hard to get a good look when it only shows a small bit of the piece at a time.
But that has little to do with the quality of the art! This is wonderful! I'm amazed at the depth and shading you achieved with such a simple tool, a mechanical pencil. Each part of the rose is extremely well-defined, accurate and beautiful. The little dew droplet details are my absolute favorite parts. They add a lot of life to the piece.