I made a quick search about programming microcontrollers but couldn't find much when it comes to OSX.
Do you have any recommendation?
Or is it better if when the time comes, I move to windows to make this step?
I don't know about OSX, I have only used the Arduino on windows. You might move to windows to start because the windows IDE is very stable and easy to use. There are lots of samples of code that can be easily adapted to what you want to do. What I do is use the arduino board to burn the script into the ATmega chip and then just use the chip on a perf board with whatever components I need....Fast,Cheap and Easy.