I find the older I get, the more an unfamiliar/complicated task gets. Then I tell myself that if I take the first step, some of the anxiety goes down, and more so with subsequent steps.
My motto in home repair and home improvements has always been, "I'm going to at least try it, and when/if I get stuck, then I can call in an expert." The fact of the matter is, in most cases I have the same or more brain power than the so-called expert - they're not smarter than me - so why not attempt a repair, use my brain, and learn something along the way. Usually, the only difference was that it took my three times as long to complete the job as what a pro would've required.