You are creating a proprietary firm.
There is no legal concept of a director in a proprietary firm.
Therefore, you should actually have designation as proprietor.
There is a law that disallows a company from designating any person as director unless the person is on the board of the company. If you are not a company, the rule does not apply. I can't find any law similar for proprietor firm. Many organisations have the post of director to designate the head of a certain function (similar to president)
But on the other hand, what is the exact purpose of the identity card ?
Is it for identification to outsiders (Like courier boys, telephone service team) or for internal (watchman will check before allowing to enter) or access control (Smart card, RFID, biometric asset). If it is internal, you do not need it. The watchman knows you. If it is external, may be visiting cards are better. You need to evaluate the purpose and how it fits into your environment.
If you are issuing one to your self just to appear part of the team (everyone in office will display it) you can issue with any designation of your choice, or even without a designation for your self.... There is no legal binding so long as it is not a misrepresentation