I notice my lo have her first tooth. But it been weeks and is like still the same. How long does it take to grow?

I have the same question because my gals first teeth sprouted when she was 8mo. She is going 13mo with 7.5 teeth but the 7 teeth that have been there for a few months all look very short and don't seem to be growing more. My gal has a bad habit of biting things not sure if that affected the growth.