Depends on your goals, really. I think a big pitfall most people think is that the goal is to learn a language, when you really should be aiming to learn confidently learn as many as possible. You'll soon start to see how similar they are, and it becomes a lot easier to pick up.
The hard part actually isn't learning a language, but a framework. Frameworks are very platform specific, concepts are less reusable. And because Cocoa Touch is so intimately designed around Objective-C, even if you chose to learn Swift first, you'll need to know Objective-C anyway because of a) the amount of code/books/resources that exists on the internet in Obj-C vs Swift and b) a solution to your problem may only be written in Objective-C in a StackOverflow search result.
As for skipping academic CS, at some point you need to learn the stuff that almost every CS grad is expected to know at some level (data structures/algorithms, operating systems I & II, algorithm complexity (aka Big O notation), software design, etc...) not so much because they'll be explicitly required of you, but as you build larger and more complex apps, without them, code readability, maintainability, and performance are going to go to total shit. Granted, there are some, heck many, CS grads who somehow evade actually knowing this stuff, and things don't turn out so great for the code they write in the end.
My advice, tackle building an iOS app with a goal in mind, written in Objective-C due to the sheer number of resources out there, then expand from there.