Whilst each tooth has an 'average; age at which they erupt, it is generally thought that up to 1 year either side is considered normal variation.
Girls usually develop dentally ahead of boys.
It is the SEQUENCE of tooth eruption that is more important than the AGE of eruption. We would be more concerned, for example, if a lateral incisor were to erupt before a central incisor, as this is not normally the case.
I would not be too concerned at this stage, but to monitor development.