(Disclaimer: what you're about to hear is my own opinion, so you may or may not agree and you may or may not think of it as petty LOL Bear in mind this is my first article too.)
I'm not very found of the new medical examiner, and it's not because I always liked Alexx. When Tara first arrived on the scene it was kind of a weird experience after the previous season's new one being killed on scene and then the one in between being a plant for the whole Horatio conspiracy. But once that shock was over, it was kind of like, wait a minute...what is she, like 22? She didn't seem old enough to be a medical examiner, let alone the head one! So I did a little research on the educational requirements for a medical examiner.
First there is the four years of undergraduate studies to earn the bachelors degree. Then there is 4 more years of medical school. After that you must complete 3-8 years (depending on specialty) of internship/residency. Which equals out to between 11-16 years. Meaning if a person begins immediately out of high school at the age of 18, they would be 29-34 by the time they have completed the requirements.
Megalyn Echikunwoke is not 22 but 25, but she is still 4 years shy of the lowest age. While I know it is just a television show, and I do no not blame her, it just goes to show that the spin off is once more trying to use beauty/sex to sell its product rather than actual even semi half reality.
A 25 year old CSI? That's more plausible as you only need a Bachelors degree and obviously in the state of Florida (according to the show) it would seem also be a police officer. But a medical examiner is a doctor, would you want you're kid being treated by the head of a hospital if if they were only 25 years old? I think not. Not even if said doctor is Doogie Howser.