None of it's "hard" necessarily, just more involved. There is nothing wrong however getting a good start with extracts before moving on to all grain (nothing wrong with staying with extracts for that matter if thats what you want to do). The basics you are talking about buying now, translate directly to all grain (large kettle, wort chiller, etc). If you decide later to move to all grain, you will just be adding some equipment, not "replacing" it. Mr. Beer gave many of us the bug, but it's pretty limiting on the imagination. Even a full extract brew, or better yet partial mash (no additional equipment needed other than a bag), will allow you to make beer to YOUR specifications and not some else's.
BTW - Welcome to the hobby / obsession!!