Female, age 57, 168 cm, 60 kg.
I used an Osprey Eja 38 litre for the French Camino last year, and felt good enough to continue on to Finisterre and Muxia (over 1,000 km total).
I found the pack very good. It has 2 huge side pockets where I could carry snacks, a water bottle, sunscreen, etc...