I think it's much better to keep things simple and easy to remember....how about "I'm a proud 'stay at home mom'" If you want, you can add that you have a few volunteer things that keep you busy as well.

If someone get's pushy with you and out of line about it, a great thing to do is ask "And why is it so important for you to know?" That usually gets the point across really well that you aren't going into it any further!