I've worked with students in China for years, and have heard all kinds of reasons for name choices. So many students would introduce themselves with names that should never be used outside of class: Chocolate, Rain, Cold, Hot, Smart, Windows, Worm, R, you get the idea. I've also heard Japanese words used as "my English name". That doesn't work, either.
I usually helped students to find names that sounded like their personal 名字, what westerners call a first name, rather than their 姓, or family name, what westerners call a last name. If your name is 周, you don't want to introduce yourself as "Joe Zhou". An English name that sound like your personal name helps your new friends to eventually realize that your true, Chinese 名字 is not so difficult to learn.
Back to your question, Tracy is a wonderful name. Enjoy it and introduce yourself to many people with it. Get used to saying "My name is Tracy (姓).", or "My name is (姓名), but my English speaking friends call me Tracy.