def main(): #The main function
    print('Hello,\nI am going to ask you your name, and your age. ' +
          'After that, I will tell you what year you were born, and what year you will turn 100!\n')

    #Local functions
    def get_age(): #Gets the age of the user
        age = input('Please enter your age: ')

        #Convert age into a number
        if str.isdigit(age):
            return int(age)
        else:
            print('Make sure you only enter numbers!\n')
            return get_age()

    #Get information
    name = input('Please enter your name: ')
    age = get_age()
    current_year = 2016
    birth_year = current_year - age
    years_till_hundred = 100 - age
    year_at_hundred = current_year + years_till_hundred

    print('Okay \'' + name + '\', we have everything done now.\n' +
          'Your current age is: ' + str(age) + '\n' +
          'Your birth year was: ' + str(birth_year) + '\n' +
          'You have this many years until you turn 100: ' + str(years_till_hundred) + '\n' +
          'You will turn 100 in: ' + str(year_at_hundred) + '\n')

if __name__ == '__main__':
    main()