Does the questioner want to ask "At what age should babies eat Ying's 3rd grade rice cakes?" September-December. According to the query on 360 Baby and Child Network, level 3 can climb smoothly (9-12 months old), level 4 can stand alone (12-18 months old), and level 5 can walk steadily (over 18 months old). Ying's is a maternal and infant complementary food brand owned by Ying's Holding Group Co., Ltd. Its series of products cover many fields including infant rice noodles, infant noodles, infant snacks, and infant seasonings.