Hi Maria,
Welcome to the Forum and I hope your pilgrimage with your friend goes well.
I don't know about 'words of wisdom', but in setting out with another pilgrim there is the element of mutual support.
However, maybe it's worth being aware of the possibility that walking in two's, or more, can create a little wall around you that makes it a little more difficult for other pilgrims to get over, and equally, for you to cross to other pilgrims. It is of course common to set out with others, but it does reduce to some extent the vulnerability that the solo pilgrim is able to experience, and with that vulnerability there can be more openness to other people and situations.
I just thought that being aware of these ideas might help you both to get a little more out of your journey together.
Buen Camino a todos,
Brendan