Yes, you can apply now. The validity of Chinese visa is 3 months, 6 months, one year and two years. Please note that visa holders must use the visa to enter mainland of China before 24:00 on the exact day of expiration (it would be issued on your Visa as ENTER BEFORE), otherwise, visa expires after time limit and cannot be extended no matter whether there is number of entry left, and reapplication of visa is required.