(I'm in my late 30s, but I always try to look for "time-tested" books first. Books that seem to hold their value after decades; see also: Lindy effect.)
Language and linguistics: "Metaphors We Live By" by George Lakoff and Mark Johnson (1980): https://en.wikipedia.org/wiki/Metaphors_We_Live_By
Systems thinking: "An Introduction to General Systems Thinking" by Gerald M. Weinberg (1975): https://geraldmweinberg.com/Site/General_Systems.html
I still often use Weinberg's Systems Triumvirate when feeling stuck on a problem:
1. Why do I see what I see?
2. Why do things stay the same?
3. Why do things change?