Your legs are fresh and your head is full of that first step. That’s exactly the danger. This first day is long, and it begins at the Somport pass, on the French border, high in the Pyrenees.
There’s hardly any climbing. You spend almost the whole day going downhill, well over 1,000 metres. That sounds kind, but it isn’t. Your knees and toes take a real battering for hours on end. The bare mountain landscape gradually gives way to a greener, wider valley. Keep a steady pace, because you’ll be on the go for about 9 hours. After all that mountain silence, Jaca is a proper town, with café terraces and a public albergue. You’ll be glad of it.
Take it easy. The Camino has only just begun.