Big tech nepotism?

My partner's mom is very respected at a FAANG company. She connected me via email with one of her coworkers (I'll call her Alice), and I went through a phone screen with Alice. I then had another technical interview with someone else on the team, which I felt went very well. I was advanced to final rounds, one of which was conducted by Alice. I felt all of my rounds went decently from a behavioral standpoint, but they lacked answers from internship experience. I had 5 rounds of intervews that I felt went average to sub-average from a technical standpoint. I produced working solutions, but felt that my system design round was subpar and I forgot some library syntax that the interviewer had to help me out with as well with some debugging. The role will be a new-grad SWE position doing data analysis/database work. I will be working to support a team of electrical engineers so it would be helpful to have some EE experience, but I do not have that. I believe they may have only opened up the portal for me to apply and then quickly closed the application. I also have average to sub-average grades. Ultimately, I was inclined and have accepted the position. Before the negative comments, I know I benefited from nepotism and I am not questioning that. I know 100% that I did not get in on merit alone and I would never pretend that I am the most qualified person for this job- that is why I am questioning the ethics of accepting the position. I have been feeling very icky about how I got the position and I am worried it was a mistake to accept. Is this stuff common is stuff like this in big tech? How bad or unethical is this example nepotism? Should I / how should I disclose the relationship to my coworkers if they ask how I heard about the position? I am assuming the HM Alice knows, but don't know for sure.