Hi Stephanie,
I walked the route from Le Puy two years ago, and am a vegetarian (and actually, I was 28 when I did it, too--so we really have a lot in common!). I picnicked a lot--cheese and tomato sandwiches, mostly, and of course chocolate and fruit. And then you can often cook for yourself in the gites d'etape (walkers' hostels) in the evening.
Also, a lot of the private gites offer demi-pension, where you pay extra and get dinner and breakfast with your stay. I found it was nice to do that once in a while, since it's usually a very communal meal, and of course the French food was always excellent. When I called to reserve my bed (usually the night before, or sometimes even the morning of), I'd ask if I could get a vegetarian meal, and no one ever refused me. The main courses basically all involved eggs. I suspect they weren't all one hundred percent free of other animal products like fat, either, so if you're really strict you probably won't want to do that.
I also met a few people who spoke basically no French, and they survived the route. But it's good you're taking a course, because a lot of walkers on that route are French, so if you can't speak at least a bit of French I suspect it could be lonely. You'll find what French you do have improves in leaps and bounds, too. I was never actually fluent, but after a week or two I could have basic French conversations without having to think about every word.
Buen Camino!
Anna-Marie
