Both my little girls cut their teeth at three months old and not in the exact order which they are supposed to come through in. The telltale signs which I soon learned to recognise with my children were fretfulness , constant dribbling , biting at their hands , red cheeks or a red spot on their cheek and nappy rash , which they only ever got whilst teething. A baby's development varies from child to child but if you are worried at all then why not have a quick word with your health visitor who I am sure will only be too glad too help x