I've been a fixer for as long as I can remember, partly because I like knowing how things work. (I do recall taking a clock apart as a teen and not being able to figure out how to put it back together, though!) My journey has been more of learning that I don't have to do it all myself, or that there are limits to how much I really want to fix things.
For instance, I could troubleshoot early Mac problems. As the systems became more complicated, I reached the point where figuring out what had to be done just wasn't fun any more and I was happy to have someone else deal with it.
In my late 20s my husband and I had a VW bus. I was the handier of the two of us, and happily did tuneups and such. I felt I could tackle anything. But after the alternator died and I managed to wrestle it out so I could bring it to a repair shop (and the guy was duly impressed), I lost the drive for doing everything myself... maybe I just wanted to prove I could do mechanics as well as any guy. I did - and then I was happy for someone else with better tools and more knowhow to do the work. (Having the right tools goes a long way.)
Now I'm 65 and living in an apartment. I'll fix some things, but there's plenty I'm happy to call in to get fixed - for free! Confidence is no longer an issue - it's more a matter of balancing interest and time.