Are you an expert in taoism, zen, the Tai Chi Classics, tai chi principles, human biomechanics, ergonomics, internal martial arts concerns, combat, how to teach taijiquan...?Probably not.
In all fairness, there is little a new student can contribute to the class in the form of knowledge, experience, insight and skill.
However, you can be friendly.
And you can also aim to practice what you have been taught.
This is your contribution to the class.