Could someone please proofread my essay?

My last visit to the library was just recently, and it ended well. I had decided to visit the Troy Public Library. It's a large library that's near my home with a lot of information on various topics. I wanted to check some books out on college level mathematics since I needed math help and didn't have any useful books on the topic at home. When I entered the library, I first tried to look up the books I wanted to find in the library's catalog computer. This was located in the adult department of the library. However, this ended up being futile because I couldn't find what I was looking for. I decided then to instead ask the librarian to ist me. I simply asked her for what I was looking for, and she looked it up on her computer. The librarian then directed me to the section where I could find everything I needed. It was the non-fiction section of the adult department which consisted of books about mathematics, programming, business, and so on. I decided to choose a few books which I thought might interest me, and then proceeded to check them out. In the library, you can check your books out at the check-out section in the adults department or the one in the main lobby. I decided to choose the one in the adult department because there normally isn’t a line there. Afterward, they asked me for my library card, which I had, and I proceeded to check my books out.