Some universities don't have age or educational background requirements.
General requirements are:
1.Non-Chinese citizen in good health.
2.18 years old or above; (If you are under 18 years old, you need to provide a notarization of guarantor in China. Sometimes a diplomatic note presented by your consulate in Beijing may be required.)
3.Hold a valid foreign passport.
4.The equivalent of high school graduate or higher academic degree.
5.A student who has studied in China and wants to transfer to another university must provide the permission from original university.