If the internship is paid, you usually need CPT authorization before starting. CPT must be directly related to your major and approved by your school. Working without authorization, even briefly, can violate your F-1 status, so don’t begin until everything is approved.

Many students get into trouble by assuming internships are automatically allowed. They aren’t. Your international student office must issue CPT approval, and the job must meet specific requirements. If you start work first and ask later, it can negatively impact future visas or OPT eligibility.

I was in a similar situation. The key step is getting written CPT authorization on your I-20 before your start date. Each school handles CPT slightly differently, so follow their process carefully and keep copies of all approvals.