Woah....you don't need a full case just because it is your first build. My first build(s) were helping to handle several mITX lab machines, and they turned out just fine. And you're still going to have cramping issues when working with a full tower because the motherboard still has sit against the back of the case.
So what you should really look for is features that will simplify your build. Compare the Rosewill Thor you mentioned to this case.
Yes, it's probably more expensive than what you really want to spend, but as you can see, both have helpful routing options and easy drive mounting options. Regardless of size, those are going to be the things that make your life easier.
And airflow might only be marginally better for a full size case depending on fans and where things are located. Larger fans can do that for you without generating a lot of noise, and having intake and exhaust keeps can keep air moving smoothly.
If your heart's set on a full tower, by all means, go all out. However, if it just ends up with a lot of empty space inside, the case is just kinda taking up space. Smaller cases are easier to deal with and give you more options with setting up your work/gaming space in the long run.
Being an adult doesn't mean you have to know what you're doing. It just means you have to look like you know what you're doing.