In order for zakaah to become obligatory, it is stipulated that one year should have passed. What this means is that one hijri year should have passed since the wealth reached the nisaab (minimum threshold), because the Prophet (blessings and peace of Allah be upon him) said: “There is no zakaah on wealth until one year has passed.” Classed as saheeh by Shaykh al-Albaani in Irwa’ al-Ghaleel (no. 787)
Based on that, if you took possession of that money three months after Ramadan (i.e., in Muharram, more or less), in 1434 AH, then zakaah on that money only becomes obligatory for you, if it reached the nisaab, in the month of Muharram 1435 AH, and it is not permissible for you to delay it until Ramadan 1435 AH.
Zakaah on one’s wealth is not connected to the month of Ramadan or any other month; rather it is connected to the time when the wealth reached the nisaab. When it reaches the nisaab, it becomes obligatory to work out when the “zakaah year” will end from that time, then pay zakaah on it, when one year has passed since it was acquired.
And Allah knows best.