To get outside the box, why are there ANY qualifications for elective office other than winning the election? If the electorate feels that a 32 year old would be the best choice for president, what's the problem?
As far as age, it strikes me (despite being on the older end myself) to make more sense to have an age ceiling, rather than a floor, since that 32 year old I mentioned gets less young as the term progresses, whereas, for example, your Ronald Reagan gets closer and closer to Alzheimer's.