Hi, Cjhubbs. One thing to take into consideration is time limits. Since you say "high school" I'm guessing you're from North America and we're limited by the Schengen rules to 90 days out of every 180 in the whole Schengen group of countries, which includes both France and Spain. So aside from whether or not it's a nice route to walk, there's the problem that you either have to do everything in 90 days or split it up into more than one trip. I personally couldn't do the whole thing in that amount of time, but you're a lot younger than I am. But it's still something to consider in your plans. If you follow the stages in the Guides LePere, they take 39 or 37 days to St Jean (depending on whether you go via Orleans or Chartres), and that includes some really long stages. Then you'd have to add on the time on the Frances, plus getting to and fro. Just something to take into account when you plan your trip.
I saw someplace that you were interested in camping, and LePere generally doesn't recommend this for France, except in regular camp grounds:
"Attention au camping sauvage ou vous pourriez vous retrouvez nez a nez avec un sanglier, un essaim d'abeilles, ou pire...un proprietaire en c0lere."
Having said that I think a couple of people here who've walked that route have camped out some.
FWIW, I do plan to walk from Paris via Chartres myself. Was hoping to do the walk at least to St Jean this fall, but will have to postpone it. There is more interest in this route in France lately, it seems, although it's still the least walked of the major routes.