My 3 y/o is obsessed with counting. She can only count to 20, has been able to count to 10 from an early age. But she will always count to ten on her fingers for any situation. Or if she sees things lined up she will always count them, or sheep in a field in the car. Even writing this post she has gone round the table counting the legs on the dining chairs. Or for example if I tell her we need to wait for something (like we are in the car going somewhere and she asks how long we’ll be) she will just count on her fingers to ten over and over until we are there. Ive noticed it a lot more over the past few weeks. Is that a concern, or do you think she is just genuinely interested in numbers?