I was introduced to the school stall by an agency to do business. I only signed the school contract unilaterally after working for a few days. Can I enroll in the school?

It can take effect.

A contract is an agreement to establish, change, and terminate civil relations between civil subjects. A contract established in accordance with the law is protected by law and is only legally binding on the parties unless otherwise provided by law. Under normal circumstances, the parties conclude a contract by way of offer and acceptance, and it becomes effective after the parties sign, seal or fingerprint it.