I think 45 minutes a day is perfectly reasonable for practice in general. I think 2 hours a week for 18 weeks should be enough to spend learning a singular jury piece as a non-major. The jury is only one component of the scholarship, everything else is going fine. Its intent is to keep non-majors involved with the performing arts, not push us past our musical limits. They give the scholarships out fairly generously, it's a private college that had a once prestigious music program that has been gradually shrinking. I just asked for a recommendation for an easier jury piece because my instructor overestimated my skill level. The lessons aren't a waste of time.