Ftm here and wondering when do kids start counting and saying abcs?

My girl is currently 21 months.

She can say the number two verbally but not display 2 fingers. When she sees two of something she says two.

she show the number 1 with her finger but not say it

When we count to three she points to the correct 3 same objects in a book.

But when do they start to really count? Was just curious