Steps for finding the lunar age of mothers :

Step 1. - Subtract the mother's 'birth year' from the 'conception year', get the result.
Step 2. - Find out if the mother's birth date was before or after the lunar new year in that year?
Step 3. - Find out if the conception date is before or after the lunar new year in that year?
Step 4. - Check the following table and add the 'additional age' to the result of step 1.

Table for additional age
Time of Conception
Birth Date
Before lunar new year
After lunar new year
Before lunar new year
Area A (+1)
Area B (+0)
After lunar new year
Area C (+2)
Area D (+1)