Hi Cassia, great question!
Using a Mac is a typical prerequisite for developing iOS apps. If you definitely want to start with iOS apps and Swift, your best bet would be to get ahold of a Mac (think about buying one secondhand - that may be more reasonably priced). That said, there are some other options for Windows users who want to build iOS apps; see here: https://learnappmaking.com/develop-ios-apps-on-windows-pc/.
Another option would be to start your journey with developing Android apps; Android Studio runs on Windows. Alternatively, you could learn a cross-platform framework like Xamarin, React, Flutter, etc.
As others have mentioned, the best way to learn to code is to use some online tutorials, jump right in and start working on a project that interests you. Best of luck!