Yes, one of the amendments lowers the age eligibility to 18. Since you have not yet submitted your citizenship application, you need to do so as soon as possible. As long as the amendment has not been gazetted, the age limit remains 21. Once the amendment is enacted, you will no longer be able to submit under the current rules.
As of December 2024, when this FAQ is being written, The Constitutional (Amendment) Bill to allow Malaysian mother to confer automatic citizenship to their overseas-born children has been passed in both the Dewan Rakyat and Dewan Negara and will now be presented for royal assent before it is gazetted. While the exact date for the gazettement is yet to be confirmed, it is expected to take place sometime in early/mid 2025. It still needs royal assent, and we are unsure of the exact date it will be gazetted. Therefore, it’s important to submit your Article 15(2) Borang B application as quickly as possible before the amendment takes effect.