China Merchants Bank does not limit the opening time of credit cards. After the credit card is issued, it can be activated as long as it is within the validity period. The credit card itself has a validity period, which is below the credit card. The standard of "05/20" means that the credit card will expire at the end of May 2020, and you need to go to the bank to get a new card before you can use it. Generally, credit cards are valid for 3 years and can be activated during this time.