Feeling unqualified for new job

Hey everyone,

I just graduated college a few months ago, and I'm going to be starting a job as a trader/quant at a well-known macro hedge fund next month. I got this job through new grad recruiting (I didn't do an internship here). 

I'm not sure why, but as my first day on the job gets closer and closer, I'm getting more and more worried about my qualifications. For starters, I got very lucky during the interviews because I think they shortened the process for me and I also got asked some pretty softball questions (e.g. stuff in the first few chapters of Greenbook), which I was very surprised by. Even at the superday, one of the interviews was just purely behavioral. I feel like they have very high expectations for me (on a technical or intellectual bar) that I am uncertain if I will be able to meet or not. I studied my absolute ass off for those interviews (for 2 months straight) and still felt shaky on some of them so it makes me worried to join.

The second thing is that I'm not even really sure what skills I learned from college. I majored in something quantitative, learned some rudimentary coding, basic machine learning skills, some random econometrics/statistics stuff, but truly nothing that couldn't be studied in a month. In my junior year and senior year I began to use AI more, so I'm not really sure how great my technical skills are anymore. I loved my college experience, but I did skip class and am not sure how much information I retained. 

The last thing is that they were very open to negotiating with me, and I don't really think I deserve the amount that I'm making. I don't know if what I bring to the team justifies the amount that they're spending.

I'm so worried that I'm going to get on the desk and everybody is going to realize that they hired a dud and wasted all their time. My recruiter told me that the role is very quantitative (math and coding heavy), so I'm frantically reviewing random things before I hit the desk, but it feels futile. I don't come from a finance background at all -- parents were very solidly middle class -- and I think joining may be a pretty big culture shock. I hope I'm not screwed 

I guess my questions are:

In general, what are expectations for new grads/new hires like? I'm 100% willing to put in the hours and the work, but I just don't really know if I have enough raw intellectual horsepower to be there.

How can I ensure that I'm the best junior I can be? I think I'm coachable and I can pick up on things fast, but are there any unspoken rules in the industry that I should know about before I join?

Is it common to feel this way at all? I didn't feel like this before my internship last summer (different firm, different role) but for some reason am getting really jittery before I join.

Thanks so much for reading. Appreciate all advice