Translations for inexperience in French

Here are paragraphs from public domain books translated:

But all three reflected upon the youth of d'Artagnan, and dreaded his inexperience.	Mais tous trois pensaient à la jeunesse de d’Artagnan et redoutaient son inexpérience.
The Three Musketeers, by Alexandre Dumas	Les Trois Mousquetaires, de Alexandre Dumas