How long did Lady Amina carry our master Muhammad (peace and blessings be upon him), and what is the authenticity of Ja'far ibn Abi Talib being older than the Prophet (peace and blessings be upon him) despite Abdullah and Abu Talib marrying on the same night?

The pregnancy of Amina bint Wahb with the Prophet, may Allah bless him and grant him peace, had no remarkable aspects other than that it was a light pregnancy, and she did not feel any heaviness as women usually do. Nor was her pregnancy period abnormal; if it had been, reports of it would have reached us. As for what was mentioned, that Ja'far ibn Abi Talib was older than the Prophet, may Allah bless him and grant him peace, despite Abdullah and Abu Talib marrying on the same night, this is incorrect. And concerning what was mentioned, that Hamza was older than the Prophet, may Allah bless him and grant him peace, this has been contradicted by other narrations indicating his contemporaneousness with the Prophet, may Allah bless him and grant him peace, and their suckling together.