All the lessons I learned from my Twenty years of my life has boiled down to a big message that the process of self-perfection is highly entangled with the effort to define the self, i.e., to find self-identity. As this identity grows broad and broad, the definition of a better self becomes tricky.
I wonder which tense is better in the clause "all the lessons I learned". I think it may be more appropriate to use the past tense, because they happened in the past. But on the other hand, this lessons seem to be stable, and not subject to change, despite coming to form a bigger message. Besides, I use present tense for the main structure.