until what age is considered infant
I had no idea there was so much discrepancy in opinion. Newborn is 0-3 months. Infant is 3-24months. Toddler is 2 until 4. 4-5 is preschooler. At 8-12 they become a tween. Teen is 13-18. Young adult is 18-29. 30-65 is middle age. 65+ is a senior.