Do I need to have completed the Level 1 internship before doing the Level 2 or 3 internship?

No, you can join at any level if you have the required background. If you are unsure of which level is right for you, visit the Summer 2021: Explanation of Project Levels/ How do I pick a level? page. You can also build up your skills towards this summer by practicing on our Pathway Hubs.