You could attempt to derive your emotional age from your EQ in the same way that one derives their mental age from an IQ test, assuming that an EQ score is given in the same format as an IQ score (where 100 is average).
If your test of choice only gives you verbal answers (weaker than average, average, stronger than average, then you can use the 15 point deviation system that an IQ test uses to where an extremely low/ lowest score possible EQ is 70, a "low" EQ correlates to 85, an "average" EQ is about 100, a "high" EQ is 115, and an extremely high/ highest score possible EQ is 130.
IQ= Mental Age / Chronological Age x 100;
Therefore, if you set up the formula EQ= Emotional Age/ 21 x 100 and re-arrange it to read (EQ/100) x 21 = Emotional Age, then one could plug in the estimated EQ and figure out a very rough estimate of their emotional age.
I do agree with BookPerson, however, on the fact that, like intelligence, emotional maturity has multiple components and multiple factors to consider. For example, you could be more aware of the implications of your actions on others than the average 21 year old whilst having weaker emotional regulation abilities than average.
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I am not a textbook case of any particular disorder; I am an abstract, poetic portrayal of neurovariance with which much artistic license was taken.