There's no given time, each child is different it'll happen just try to be a little patient. Enjoy this time with your little one they grow up far too quickly.
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.
My son had the opposite. The new tooth came out and the old was still there. It took 6 months for the tooth to fall out. I took him to the dentist and the dentists said that sometimes it will take about 6 months for a new tooth to come. I gave my son tissue salts called Calcarea phosphorica to help assimilate calcium.