Being ambitious for fulfilling your calling, supporting your family, and creating a positive impact in the world is a great thing. It reflects that you believe in the power of giving, fulfilling your responsibilities, and in making the world a better place.
Being greedy on the other hand means that you care only about your fame, power, and ego, thus the more you have, the less it appears to you.
There is a fine line between being ambitious and being greedy. Some people go to extremes to become powerful and famous at the expense of their family, balance, and impact to good causes.
Thus be ambitious as your spirit, family and the world needs you to be that. However, be on guard for not getting into the greedy territory in the guise of ambition!