NBCUniversal Cable Entertainment Group Chairman Bonnie Hammer recently turned 65, and to commemorate the milestone, she’s penned a frank and enlightening op/ed for Fortune magazine on being older and female in Hollywood. It touches on a topic that has been the subject of much debate lately as studies suggest that the film and TV industry is still not very welcoming to women of any age behind the scenes and not very kind to women over 50 in front of it.

In her essay, Hammer, one of TV’s most powerful executives, is a defiant acknowledgement of the situation. “I celebrated my birthday last month, and for the first time in as long as I can remember, I was completely open about my age,” she writes, noting how from her perspective, the problems with how women are treated as they age seem amplified in Hollywood. Her solution: Women in Hollywood should “rewrite the aging script.” Embrace the aging process, stop hiding from it, and set an example for younger women coming up behind them. Some highlights:

While leading men have been celebrated for their timeless charm and weathered good looks, women my age have been barely visible on screen—or try to remain visible by remodeling what age has created. Bowing to societal pressures, they’ve lifted brows, tightened skin, filled laugh lines, and realigned proportions, all to stretch careers that would have otherwise been jeopardized by simply looking one’s age.

Ask almost any woman in her 60s and she’ll tell you that while she may feel like 40—vital, vigorous and engaged—her valuation has changed. Experience is often dismissed, energy routinely ignored and, let’s face it, sex appeal all but laughed at. In racetrack jargon, we old mares are sent out to pasture while our male counterparts frolic in stud farms.

To put it bluntly, I feel relevant and valuable and I am struggling to understand why, when women reach age 65, they encounter an invisible barrier of perception that says it’s time to walk away. Shouldn’t we have a choice in the matter? Shouldn’t our experience and energy be worth more?

I believe that women everywhere would share that same profound sense of freedom and possibility if they simply ignored the constraints of conventional expectations—including what it means to turn 65.