Sayyiduna Maslamah bin Mukhallad (may Allah be pleased with him) said: When the Prophet (peace and blessings be upon him) arrived, I was four years old, and when he (peace and blessings be upon him) passed away I was fourteen years old.
Imam al-Tabarani (may Allah have mercy on him) said: The narration of Abd al-Rahman bin Mahdi is the correct one in my view, and Allah knows best.
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17110