Hi Suzie: Keep in mind that as many as 200,000+ people walk the Camino every year. You are never alone. It has been my experience on my many long walks that, if possible, you should plan on going alone. Of course, if you have a spouse or direct relative that wants to go, then make an exception for that. Even though I did walk it with my wife, we spent a majority of the time off hiking with new friends and found each other at the albergues in the evening. Prior to that, I had hiked the entire Appalachian Trail, on the US east coast, all 3000 km, and I did that solo and loved every minute of it. There too, I made a ton of friends. The Camino is an opportunity to meet many new friends and that will happen. It is almost impossible not to make friends.
Planning on hiking with someone that you don't know well is likely to fail. First and foremost, most people just don't travel at the same rate and one will be held back and the other will feel stressed trying to keep up. This is a long walk, natural rhythms will sort out who you enjoy hiking with...believe me, it never fails. Let the Camino sort things out. If you 've seen the movie, The Way, with Martin Sheen, the one thing that I thought it captured best was the friendships that formed, and in the movie, he was trying not to be friendly. I've found friends on the Camino in 2011 that I correspond with regularly, and from several different countries.
As for three months, I think that is a good idea. I walked it in 43 days, and wish I had taken more, just to absorb the culture and beauty of the Camino. If you finish early, there are plenty of other things to see and do and other, shorter, walks worth taking. I found Sept/Oct. to be the best time to walk, the weather was fantastic and not too hot or cold. If I had three months, I might start in August, it will be hot, but just plan on short days.
Keep us posted on your progress, I always love to see how things work out.
Dennis