For most of us, getting older doesn't necessarily make us happy. Birthdays definitely don't seem as exciting as they did 15 years ago. Regardless, it has recently been reported that 90% of employees over the age of 50 find themselves somewhat or very satisfied with their jobs.
Although the study found certain minorities who have experienced negative age related comments in the workplace, the majority of workers over 50 feel a solid sense of job security, which results in satisfaction with their jobs. Most of these workers have spent the previous decades climbing the career ladder, and are now able to enjoy the higher salaries and increased job security they have always wanted.
So although getting older may be somewhat of a drag, it is likely to lead to a higher level of satisfaction with your career.