As others have said, you need to verify that with your health plan insurer.
That said, "the 'under 26 rule' allows young adults to stay on their parents' health insurance plan until they turn 26, regardless of their marital status, living situation, or financial dependence. This rule, a provision of the Affordable Care Act (ACA), applies to most individual and employer-sponsored plans. When a dependent turns 26, their coverage typically ends, which triggers a Special Enrollment Period for them to find their own health insurance."
