It is required. Wherever you are staying, ask the front desk / landlord for a copy of the TM30 they are required to file when you checked in to their property. If not available, then you must furnish your booking details as an alternative.
For those who are interested in the minutae, both Thailand and Myanmar's citizenship laws are based on Jus Sanguinis(birthright by blood) whereby one's status is acquired at birth based on the citizenship of the parents at time of birth. This is different from Jus Soli(birthright by soil) whereby one's status is acquired based on the soil upon which the birth took place. Therefore, without knowing what mother's citizenship(based on her birth certificate indicating her own parents' citizenship upon her birth) and also child's citizenship(at minimum child would be citizen of OP's country-German?), it would be impossible to give any correct advice as to whether OP has any option of applying for visa to visit 'Thai Family'.