Never take a full roller near a ceiling edge — it leaves a fat ridge you'll need a ladder and a brush to fix. Unload the roller out in the field, then work back toward the edges with a near-empty one.
A loaded roller carries too much paint to start at an edge. Dump it in the middle of the section with firm pressure, spread it out to the edges with a lighter roller, then finish with near-empty passes at almost no pressure.