Lillian,
You don't provide us with clues about yourself that would help us judge if you are capable of walking or not. Details like age, height and weight, smoker or non-smoker, medical conditions - diabetes, heart condition, asthma.
(age is not a strong indicator as there are pilgrims 80 years old and older, but these people probably have a very active life style and no other issues.)
So I'll assume you are "average" in every way and have no health issues.
You are probably on your feet, bending and stretching, a lot every day running the B+B. This will help you.
Some pilgrims do the Camino without much preparation and get through without serious problems.
Others, including some who have trained for months, suffer severe blisters, tendonitis, knee and hip pain or general exhaustion. This is often due to trying to go too quickly, particularly at the beginning and during the first week. Aim for 18 to 22 kms per day for the first week, and once your body is accustomed to walking with a pack, you can adjust your distance each day. The only exception to this is the first day, Saint Jean Pied du Port to Roncesvalles, which is up hill and 27 kms. Start early in the morning, walk slowly and methodically, and take a lunch and 2 litres of drinking water.
The only other thing I would suggest is to be very deliberate in keeping your pack weight to about 10% of your body weight, and under no circumstances heavier than 10 kgs. (22 lbs) There are several good threads on this forum that provide lists of what to bring.
You won't have any problem walking alone. There will be lots of people on the trail. At most times you will be able to see another pilgrim if you look foreward or back.
And finally,
Be prepared for the experience of a lifetime. Not in thrilling moments, but in a general peace and sense of wellbeing when you are done.
Ultreia , Onward.
David, Victoria, Canada.