Nobody can promise that. The official description of the process speaks in weeks, but it is not a guarantee, and the case ends with an EB-1 or EB-2 determination subject to visa availability. Treat the birthday as fixed and the process duration as uncertain, then ask counsel what that combination means before paying.
Remove the delays you control
The parts of the timeline a household can influence are document collection, translations, medical appointments, and responsiveness to official requests. Handle those quickly and the remaining wait is at least not lengthened by the family itself. Have civil records and passports in hand before the application rather than ordering them afterwards.
Where a request for further documents arrives, answer it completely the first time instead of in instalments. Handle the parts of the timeline the household actually controls and stop treating the rest as manageable. Collect civil records, passports, and translations before the application rather than ordering them afterwards, book medical appointments promptly, and answer any request for further documents completely the first time instead of in instalments.
Those habits do not shorten the process, but they ensure the household is not itself the cause of delay. The official description speaks in weeks without guaranteeing anything, and the case ends with an EB-1 or EB-2 determination subject to visa availability. Treat a fixed birthday as fixed and the duration as uncertain, then ask counsel what that combination means before paying.
Record the advice given.