Some babies are born with teeth, so don't be alarmed if yours starts early. The average age is 6 months. My first had most of her teeth before 1 and the second only started getting her teeth after she turned 1 (yes I was worried, but her teeth are all here now and she's fine 😅)
Our first started getting his teeth at 4 months, and they came through really fast. If you use a very clean finger, you may feel buds on their gums. Their teeth move around a lot before they get right up to break through the gum, so it could be the teeth moving around under the gums, getting in position and ready to come through. Sometimes, they can be quick or take a while.
I would be interested to know too as our little girl is just over 9 weeks and doing the same thing x