Perhaps it was not tuned well. And also maybe your fingers cant press down hard enough for the proper sound of the chords. Give yourself time. The callouses need to form, buy a tuner(you probably have one already) Get some private lessons. An expert can figure out the problem immdiately simply by watching you press down on the frets and the way you strum. Last but not the least, try to enjoy yourself. You will get better and better as the months go by.