I think asking advice like this can be super tricky. Your age, true fitness level, weight and a variety of other factors all play into what you may or may not be able to reasonably walk. You are also walking your first camino which adds to your stress and uncertainty. As others have said you can walk part way to Orisson the day before if that is feasible. You could walk Valcarlos but as trecile says:
And you can use a luggage service to make your load alot lighter.
They are not done to scare pilgrims. They are done to scale. If the size of the map and the distances between each kilometer were larger than the sloop would appear to be far less steep. These stage profiles of the type of terrain you will encounter, how steep uphills and downhills are and the distances between villages can be invaluable especially on far less traveled caminos with far less infrastructure. It is also difficult if not impossible to ascertain another person's age fitness level, and experience as a hiker or pilgrim. Your fitness and comfort level and definition of a good day's hike may be far different than he person walking next to you. There is also the question of how long someone has walked before they approach a very steep hill or pass. I walked my first camino after training for months with a friend who is a triathlete before my first camino and I thought I would die when I got to Orisson. I was 58. I walked from Le Puy 3 years later which is a far more difficult camino to walk and when I walked from SJPP it was an absolute breeze.
I have walked many caminos over the years and I think the most important lesson a new pilgrim who is not sure of their fitness level or not sure of anything is to learn to listen to your body. Pushing yourself can be a recipe for disaster even on the first day. I have walked physically difficult caminos like the Norte and Le Puy and maybe even more difficult mental caminos like the VIa De La Plata. I have learned as have many others here that you walk when your body tells you, stop to rest when your body tells you, and eat when your body tells you. Pushing your body to its limit, especially if you have no real idea what your limit is can be dangerous. Like for all of us, what is easy and doable for one person may be really difficult and injurious for another. Buen Camino
I think your other advice is spot on that the poster should consider.
