You might be right, but I was just speculating as well. The only thing we can say for certain is that they reach adulthood sometime between 40 and 60 years, and that Liara was a young adult In ME1.
Personally I'd prefer 50 or so to be the age they reach adulthood however, rather than Liara having a backstory as a child prodigy. She's already got enough characteristics to make her stand out from other Asari without also being Doogie Hauser, PH.D.
I don't know if Asari "children" shouldn't be earning the equivalent of PhDs. I mean, they've got to be doing something with their time, I doubt they're supposed to be stupid, and they've still had 50 years to learn things.
Asari ages shouldn't map smoothly onto any human age equivalent, because you can't just stretch out childhood, puberty or young adulthood without changing them. If you've got 45 years of learning and life experience you're not the same as a human teenager, even if physiological and social factors mean your not really the same as a human adult either.