The idea of a teenager being a genius is much, much less far-fetched than the idea of the Iron Man armor being viable in the 1960s (or today). Teen geniuses and child prodigies are a real phenomenon, documented throughout history
. And I find the show's portrayal of Tony as a prodigy to be very believable and true-to-life. He's accustomed to being home-schooled and learning at his own pace, and finds conventional school to be tedious beyond belief. That's very realistic. The only unrealistic part is that he's in high school at all; realistically, a genius of his level should be earning his second graduate degree by his age. But in-show, the decision was made for the sake of developing his social skills; his father felt that having him be among kids his own age was more important. I can buy that as a justification. It's still a lot more credible than the Mandarin's ring powers or the Living Laser.