Reverse age discrimination, or showing prejudice against a person because she is young, may be one reason Mercer Human Resource Consulting found that only 44% of employees ages 18 to 24 believe they are treated fairly on the job (compared with 64% of employees ages 45 to 55).  In most states, it’s actually legal to discriminate against employees because they are too young.  Fair Measures Corporation confirms that U.S. law only protects people against age discrimination if they're 40 or older.

You must prepare for the challenge of being judged according to your length of time on earth.  Some colleagues will expect you to act flaky or immature, others will assume you’re already looking for your next job and aren’t serious about the company.  If you want to move your career forward, the burden is on you to prove them wrong. 

Pay close attention to your appearance and how you introduce yourself around the company to ensure that you come across as a mature professional.  A manager once told me if I dressed and spoke assertively like the VPs, I would become one faster because people would be able to picture me in a higher position.  Remember that opinions formed on the basis of initial impressions are very difficult to change, so when you first work with older colleagues, project enthusiasm and do the best possible job on every assignment.  Don’t let your age become a regular topic of conversation.  Instead, give them something better to talk about: your talent and bright future with the company!