No!  There is no problem with taking a test, however ultimately only YOU can determine your type, based on your own self-study, which may be embellished by test results or the observations of a professional.

The Enneagram is a complex system with great depth and breadth.  One study revealed that 38% of Enneagram test results were innaccurate.  The more evolved you are, the harder it is for a test to accurately determine your type.