I think 'first time' Pilgrims always feel anxious. I know I did! And I started out not having walked in 6 weeks due to training injuries
The first time I actually carried the pack I was taking on the Camino, was on the way to the Airport .... I was 58, injured and 10 kg overweight. If I can do it, you can
You sound like you'll be fine.
For a start, the sheer 'reality' of finally being on your Camino is a huge motivational boost. After all your planning time you are finally there, and nothing is really going to stop you... It's like training for the 'big game' and suddenly you're out on the field with the rest of the team!
Lose some weight! In your pack
Maybe 2-3 pounds of that stuff that you 'might' need or could easily do without. (you don't 'need' 17 lbs) Your feet will feel every pound of additional weight.
Start Slow. Take it easy the first couple of days, ease into it. Maybe walk shorter distances on those early days. You can speed up later....
And it's not a race! OK, many people have time constraints and feel they 'must' walk a certain distance each day. But if you can loosen those constraints a bit you will feel better for it. Listen to your body. You'll be acutely aware of how it's holding up. And stop to fix anything that doesn't feel right, before it gets worse.
Although I was one of the slowest walkers I met, if that makes sense, I still mostly kept up with my Camino families. Sure I walked slower, but I just walked more hours. Taking lots of breaks along the way. Boots and socks off, elevating my feet and so on. Lots of stretching. I just drifted in an hour or two later than the others
And lastly, IMHO, the Camino is not so much a physical challenge so much as an emotional one. You can 'deal' with the physical stuff. Sure it can be hard, but you can 'deal' with it as required. But the emotional roller coaster? That can knock you flat very easily. Just remember why you are there. All the planning that got you there. All the awesome people you are meeting and are still to meet. The wonderful places you are passing through.
At times when the emotional challenge was tough, I often paused in a local Church. Or even by a roadside cross. Just to reflect on why I was here and what I hoped to learn from my journey. And to give thanks for making this journey possible. You don't need to be religious. It's not about the church or the cross per se, but making a connection.........and seeking moral support. Which always seemed to come in one way or another....... I had some very 'down' days. And my spirits were always lifted.........just when I needed it most.
There are some 'Camino Moments' on my Blog. I didn't share these at first as they are deeply personal, but what the heck. It's all part of the journey.
http://robscamino.com/category/camino-moments/
Just keep going, one foot in front of the other, speed and distance don't matter. You'll get there
P.S. I was at a local clinic today getting Ultrasound Guided Cortisone injections in my Achilles Tendons. (My training injury from last year). We're off on Pilgrimage again in 4 weeks! Yippee