You've worked hard to get this opportunity and you want to make sure you get the most out of it. During the remaining weeks of your internship, think of this opportunity as a chance to "try on" a new role, or possibly several new roles if you're given the chance to rotate through different areas of the organization.
Ultimately, there is no way to be sure that the so-called right decision has been made before it has been made and acted on. All you can do is ensure that the process of decision-making is deliberately and painstakingly executed. That doesn't guarantee the best decision, but it sure makes it a lot more likely.