Should MPs be a minimum of 30 years of age and have had a real job before they become MPs?

Tony Blair has been making the point recently as reported here:
http://blogs.telegraph.co.uk/news/suecameron/100243793/should-we-insist-on-older-mps-and-clear-out-the-adolescent-spads/
For my part I became an MP in my 40's having done a number of different jobs. It has definitely stood me in good stead.