So the relationship between the two functions is not linear, but logarithmic. Also, if we assume that humans age at a linear rate, we may possibly find that another species, compared to us, biologically ages at a varying rate over time. Math is fun and interesting for people who are open to it.
Conversion from one thing to another is not always linear. For example, translating the New Testament from Greek to English is not a linear, word for word process. Many words and grammar and syntax and connotations do not equally exist in both languages. The end result varies according to the various schools of translation ideation, and none will be both faithful to the original language, and comprehensible in the target language.
Thanks for the interesting topic!