A 'supermoon' really is bigger, about 14% wider and 30% brighter than a full moon at its farthest. You will almost certainly not notice.

The orbit is an ellipse, so the distance swings between roughly 356,500 and 406,700 km. The difference is measurable and photogenic side by side, but there's nothing in the sky to compare against in the moment. What people are usually reacting to is the Moon illusion near the horizon, which is a separate thing entirely.