How far is the earth from the edge of the Milky Way galaxy?
You must consider one thing however, there is no way for us to look down upon our own galaxy as we might with the Andromeda galaxy for example. Astronomers have done their best to replicate what they think it looks like and where we sit within it.
image from www.daviddarling.info
This is one representation of what our galaxy may look like. As you can see we are pretty close to the outer edge.