I know there have been several threads on this, but I really need some advice for my situation!

I have been with my company for almost 2 years, and in the last two weeks, I have been given a new role in the company to oversee our own products. I had never worked with our own products before, so it's almost been like learning a completely new job. They are having to train me in several different aspects of this new role. My boss is really excited to have me in this role, so that he can have some consistency in the management of our products for the long term. However, I am five weeks pregnant and I know I want to be a stay at home mom when the baby comes in June.

If I didn't have this new role, I would probably just tell them around Christmas time, when I'll be starting my second trimester. But should I tell them earlier so that they can rethink their long-term plan, and possibly start training someone else to fill this role instead of me? I really like my boss/co-workers, and I want to leave on good terms so that I can possibly come back when the kid(s) are older.

What would you do?! Thanks so much for your advice!