Every child will reach key developmental milestones at slightly different times. This is perfectly normal. However, in most cases, you can expect your baby to begin to hold their head up at around 2 months of age. At this point, they may also start learning how to push themselves up with their arms during tummy time. At around 4 months of age, your baby should begin to support their head on their own. At around 6 months of age, your baby will likely be able to sit up with a little help and support. At around 9 months of age, your little one will begin to sit up on their own without needing any extra support or assistance.