Sounds like it could be a good choice for you. The fact that you bought a code book tells me your not afraid of digging into a book. I'm relatively new at building inspection, a little over 3 years. 4 years ago I would never have thought "hmm maybe I'll be a building inspector." I applied for the position on a whim after a second year at my last job without a raise. That's another story though, I'll stay on topic.
Upon getting the job I was given 1 year to pass the Residential Building Inspector Certificate which I was warned was very difficult, some said the most difficult. I decided to take the test early for two reasons, first was I didn't know what the test would be like, and second I might pass. I figured it was worth $210 to see what the test was like, valuable learning experience, and heck if I passed great! So I took the test 2 months into the job and passed. The next requirement was to get the commercial "combo" cert within 2 years which means passing the commercial building, plumbing, mechanical, and electrical. I got those within my first two years easily with time to spare. I'm technically not required to do any more, but I went ahead and did the res plumbing, next is res mechanical, res electrical, then the plans examiner cert. From there I will probably go for the 3 part CBO.
The tests are not easy, but they are not insurmountable if you take the right approach. It's not about knowing every code off the top of your head, it's about knowing where to find it. They are open book exams so with unlimited time almost anybody could pass them, that's why they are timed. I think the most important preparation you can do is the mental time management. I recommend trying to get through the entire exam in less than half the allotted time. Answer every question. If you feel reasonably confident of the answer off the top of your head answer and move on, if not spend two minutes looking for the answer. If you can't find it in two minutes, guess, flag it, and move on. If you do that you can get through in less than an half the time. Then you can go to work on the flagged questions, but still don't spend too much time on any one question because, ideally, you will leave yourself enough time to quickly go through every question quickly at the end and look for the "doh!" mistakes than you made because you're rushing through it.
That's my approach and it's worked so far. If you have any certification prior to applying it will look good, and if you have more than one I think you're a major step up. From what I hear only "experienced" inspectors show up to an interview with certs in hand.
