She totally hand-crafts (mouth-crafts?) her cardboard boxes to be comfortable hideouts for her.

The concepts you should know/are expected to know are really going to depend on the company you’re working for and even the team within it. In general as a new grad you’re expected to be learning, and you will slow down the dev that’s assigned to be your mentor. That’s 100% okay, it’s part of their role as a mentor to be interrupted by you and help answer your questions so don’t feel bad about asking for help when you need it.

One useful skill you can start to pick up immediately is learning how to discover things within the company. If you ask your mentor a question and they just give you the answer, don’t hesitate to ask them to show you how they got to that answer. Whether it’s debugging, navigating documentation, etc, the most successful new hires I’ve seen have been ones who have showed that curiosity and used it to learn how to navigate within the company’s codebase/systems.

Another big change when you’ve only done internships in the past is to remember that your career is now a marathon, not a sprint. During an internship you often have a fixed amount of time to achieve a set goal so you can push hard and get there, knowing you’re done at that point and can take a break. Now that you’re working full time there will be more work waiting for you so if you keep pushing too hard you will burn out. Through trial and error you’ll need to find a pace that you can work at sustainably over an extended period of time. Yes, there will be times when you have to push hard for an important deadline or if things are on fire, but hopefully that will be the exception and not the rule. I don’t have any good advice for proactively avoiding burnout though. It’s something that you have to learn by experiencing it and trying to reflect and see if you can identify any early warning signs. I’m almost 20 years into my career now and it’s only in the past 4-5 years that I’ve started to be able to catch burnout before it happens and flag it to my manager.