There were several skilled mechanics in my family, chief among them my father. Dad tried to discourage me from things mechanical on the theory you can earn more $$ with your head than your hands. I have the degrees and lifestyle to demonstrate he was correct but growing up in Nebraska, there were enough friends & cousins fiddling with tractors, old trucks & cars for me to gain some knowledge. My inherent cheapness & curiosity cause me to always try to fix things myself & bikes aren't that complicated.
My oldest son is an extremely analytical type with degrees in Mathematics & Chemistry. Growing up, his best friend (now an auto mechanic) was one of those take it apart & see how it works types. These two cleaned/lubed & maintained their own bikes and once disassembled & successfully reassembled a Sturmey Archer 3 speed hub when they were twelve. They used rags to catch parts, my son Jeremy sketched things as they worked & Charlie did most of the work. They were quite a pair and today both can repair just about anything. The best approach is tempering the "take it apart" impulse with some thought & analysis. Don