it's simply a "slang" words derived from"maaf". In the context of your sentence, it can be quite offensive for some people to be asked a private information, hence appology in the beginning.
Itu adalah rencana yang baik!
Fyi, actually, Bahasa Indonesia and Bahasa Malaysia are two different languages. Even though those languages sound similar to foreigners. (because Bahasa Indonesia and Bahasa Malaysia are both come from Bahasa Melayu. And, sometimes, Malaysian and Indonesian people can understand each other). Therefore, I encourage you to google it and find the difference between those two. :D
And If i may advice, if you want to learn Bahasa Indonesia, please come to Indonesia area and if you are interested with Bahasa Malaysia, there is nothing better than learn it from Malaysian people.
May the force be with you!
