Thank you for your query,
The mean head circumference for a 1.2 years female is 47cm. Your child head circumference is low according to CDC growth charts but nothing to worry as all her developmenta milestones are normal according to your history.
After 2 years of age vision should be checked objectively by an expert according to well cilld visit program and below 2 years the testing is subjective by observing her sight by her paly, holding and reaching objects.
As the developing milestones seem appropriate for the age, we can expect her cognitive function should be good but be in regular follow up with your Pediatrician
Hope i have answered your query.