Aloha and welcome! You're too right about all of it; pin trading is an extremely easy habit ... er ... hobby to get drawn into - and once that happens, it very easily can become quite the obsession. I think you were (and are) very smart to decide on a theme to collect. With any collectible-based hobby, I would recommend patience; never 'need' something so badly that you rush into a transaction where you give up too much to acquire it. Given enough time, I believe that if you're meant to own a pin, it'll find its way to you eventually, whether through a trade, sale, or zap.
If you have any questions, please don't hesitate to ask. We all were new to pins once and we know that asking is the best way to learn.