Lantern B was made by a 10 year old boy (clue 1). Lantern A was made by Natalie (clue 2). Justin made lantern C (3 and above), so Tim is the 10 year old boy and his lantern is at B (1,5 and above). By elimination, Melissa's lantern is D and the one made by the 12 year old is C (4 and above). Natalie isn't 13 (2), so 11. By elimination, Melissa is 13.