Bollywood superstar Aamir Khan turned 50, and started his celebrations early by cutting a cake with media persons. The actor was sporting a beefed up look for his next film `Dangal`, said he still feels like he is in his early 20s. Aamir thanked the writers and directors with whom he has worked to gain stardom. Shah Rukh and Salman also share the birth year of 1965 with Aamir and the actor joked that their combined age hovers between 18 and 20. Aamir said in three years they will only turn 25. Aamir is shy about celebrating his birthday and attributes his success to a combination of hard work and luck. He admits to having learnt a lot from mistakes and failures. Failures taught him what to do and what not to do, he said. The actor has piled on 22 kilos for `Dangal`, which starts filming in September. Aamir says it is always difficult to undergo the great physical transformation for his films.