What you heard is only partly correct. Your question can only be answered if you state the exact code section you were convicted of violating. The length of the sentence is not always the most important fact when determining whether a conviction makes a foreign national deportable.
You need to get copies of the conviction documents in your criminal case, and take them to an experienced immigration attorney who specializes in deportation defense.
Law Office of Lamar Peckham
555 Sebastopol Rd., Ste. C
Santa Rosa, CA 95407