A baby has stated to get his first milk teeth. His age is approximately:

Most babies have their first primary (milk) teeth erupt at age 6 month of age and first secondary teeth erupt at age 6 years. The teeth in the upper jaw erupt earlier than those in the lower jaw, except for lower central incisors. The lower central incisors appear, commonly, between the ages of 5 and 8 months. The upper central incisors appear a month later and the lateral incisors usually within the next three months. The first molar teeth appear around the age of 12-15 months, preceding the eruption of canine teeth by 6 months, which appear between the age of 18 and 21 months. The second molars are out at the age of 21 to 24 months. Note: Permanent teeth eruption is in the following order: 1st molar - 6 years; central and lateral incisors - 6-8 years; canines and premolars - 9-12 years; second molars - 12 years; third molars - 18 years or later. Ref: Ghai Essential Pediatrics by O P Ghai, 6th edition, Page 6 ; Nelson Textbook of Paediatrics 17th edition page 18 & 37