One month notice?

So I have been working at my current job for over a year and a half. I am in charge of teaching 39 preschool aged children how to read. Not all at the same time, but by myself which at most times can be extremely stressful. I also recently found out I’m pregnant (8weeks), and I am a full time business student taking 18 credit hours. I made the ultimate decision to look for a new job only because this will not work out with how busy my life is about to get. Long story short, is giving a one month notice bad? Or should I wait for the two weeks? The only reason I want to give one months notice is because I want them to have enough time to find someone who can take my position and so that I can train them. Is this a bad idea? Am I being “too nice”? HELP