In Star Wars - hyperspace travel has some limitations. For one, you can't get to close to a gravitational body.
We see this in Ep IV - the Falcon must lift off on repulsorlifts and travel at sublight away from Tatooine before entering hyperspace.
I seem to recall something in the novelization about "six planetary radii" when it explained how the Death Star moved using hyperspace and sublight engines.
In the now Legends canon - this gravity limitation was the explanation for the Kessel Run being measure in parsecs (basically, how much of a corner a ship can cut past a cluster of black holes), and even used tactically by the Empire with their Interdictor cruisers.
So, in the new film, how could the Falcon fly through hyperspace to get under the Starkiller Base shields?