Will anything happen if you lie about your age on an application? I don't see how your age, race, or sex should be taken into consideration unless you are doing a job that requires strenous physical labor.
In the UK it is against the law to ask people for their age on an application form (eg: no date of birth field). Also against the law to ask questions at interview which can be interpreted as ageist. The only exceptions are for legislated occupations such as joining the armed forces.