Well, if I'm anything to go by, you can be a totally inexpert idiot. *g* Seriously - compiling a kernel in a true expert fashion... well, you might need to be Linus, I guess. But getting a reasonably slim kernel that does what you want it to isn't that big of a deal, at least using the simple text-menu interface which has a lot of assistance. Along with all the docs in the kernel source, as long as you know your hardware and your aims, you should be okay. It's really not all *that* different from compiling a really tricky, picky app. If you don't know how to install something without pointing and clicking, you're not ready. Otherwise, go for it.
I had to guess at some of my hardware, had minimal aims - get CORE installed on my ancient hardware - and my first shot resulted in a functioning kernel that I left some stuff out of, so the second shot got it more or less right. Basically, the task of compiling the kernel will itself give you some experience. You'll find out some things that go into it, learn some things to research, etc. I think it would be harder with more modern and complex hardware and, thus, more options in the software, but not categorically different.