It depends on how much time you dedicate to practice and draw. But most of my students see a considerable (and big!) progress after the first couple of lessons.
Actually, one of my students, who had 0 experience in drawing, felt that her first drawings looked like childish ones. But, after a singles weekend with practicing my method, she was surprised that she could create her own fashion sketches.
So, this course (its method) allows you to grow your skills faster and easier, and as you practice your abilities get better and better.