Hello, Moon Seok-jin! Even though it's basic, object-oriented concepts such as classes and inheritance are really, really important. The difference between knowing and utilizing them well and not is huge, so I want to tell you that you made a really good choice to take the basic course. 👏 Studying once doesn't mean you'll have everything, but since you studied again, your perspective will be broader when you proceed with your project, and you may even think, 'I wish I had done it this way' for the projects you've done before. I sincerely congratulate you on completing the course. 😊 Thank you. - I also code