Is ambition good or bad? It's a great question. I have it asked of me all the time. And here's my answer: it depends! It depends on whether it's selfish ambition or not. Selfish ambition will use illegitimate means to accomplish legitimate ends. It will cross over boundaries of propriety to accomplish its ends. That’s not good.
However, ambition to succeed and be the best you can be in any field of endeavor is a good thing. You will never use illegitimate means to accomplish legitimate ends. You know that's not right to do. But you will try, within right rules and ethics, to become all that you can become.
Therefore, be ambitious. Work hard. Try to succeed. At the end of the day, look back and know you did all you could do to be the best you can be. But be careful of selfish ambition. Eventually, it will motivate you to do things that are hurtful to others…and eventually to yourself.