The case is purely personal preference as long as it does what you need. When I first started building about 15 years ago, I got whatever I could afford. I became an enthusiast after that and preferred larger cases. They provide more room to tuck and hide cables (especially if you used heat shrink), and more room for larger fans for better cooling. I was very intense into PC building around 2004. Trying to find the perfect pairing of CPU with memory that had great latency (good CAS/RAS timings). This is back when FSB was actually a thing and you had to take it into account if you were ever going to overclock successfully. These days I go for small and quiet since my only desktops are a media center box and a server I use for training.
Anyway, good for you Saddam. It is great that you are doing it. If you need any help, I'd be happy to assist. I've built more than 200 PCs in the past 10 years, so I know a thing, possibly even two.