According to a report, millennial and Gen Z women experience ageism the most: "I was frequently doubted about my choices."

Burnout and leaving jobs altogether have resulted from the numerous microaggressions that Courtney Chatterton has encountered in the workplace due to her age and gender.

After graduating college, Chatterton, 27, recalls her first job as a marketing operations role at a small tech startup in Chicago, Illinois.

""I collaborated with individuals who were significantly older than me, and despite being expected to lead projects and make decisions, they consistently belittled me and questioned my choices. As a result, I felt unsupported and utterly defeated," she shares with CNBC Make It."

She frequently felt isolated due to her age and gender, which was exacerbated by working in a male-dominated workplace and being the youngest staff member. After 18 months, she made the decision to resign.

According to research from LeanIn and McKinsey & Co., younger women are more vulnerable to ageism in the workplace than older women.

Older women and men experience ageism at roughly the same rate. However, women in their 20s and 30s report higher instances of ageism than older women and their young male colleagues.

Women in their 20s and 30s are more likely to report that their age has negatively affected their career than women in their 40s and 50s.

More ambition but fewer sponsors

Young men are less likely to receive unwanted age-related comments from their co-workers than women in their 20s and 30s.

These behaviors could include excluding younger women from leadership opportunities due to the belief that it's "not their turn yet" or making jokes about their appearance and lack of experience.

In her 20s, while working as a recruiter, April Little, now 37, was often told she was "overly ambitious."

She was denied professional development opportunities and a title change when she asked her bosses, while her male colleagues with similar credentials were rewarded for the same behavior.

"Little, an executive communication coach, recalls that many of the young men she worked with initially joined their job through a referral from an older male colleague who served as a mentor or friend. This support can shield them from age-based discrimination."

Young women are less likely to be hired into entry-level roles or promoted to manager positions, according to LeanIn and McKinsey. This is often due to a lack of sponsors who advocate for them and provide opportunities for career advancement.

"According to Rachel Thomas, LeanIn's co-founder and CEO, we typically advance men based on their potential, while women are promoted based on their past achievements. Young women frequently encounter greater obstacles to career growth."

The unique workplace problems Gen Z, millennial women face

Ageism can hinder women's career progression at any stage of their lives. Young women may be deemed inexperienced and therefore less likely for promotion, while middle-aged women may be viewed as having too many caregiving responsibilities.

Thomas notes that older women may experience less ageism due to their greater experience, seniority, and professional networks, which can provide them with protection from such biases.

Emily Levine, executive vice president of Career Group Cos., suggests that the higher rates of ageism younger women report could be due to generational differences.

"According to Levine, early career professionals, especially Gen Z, are highly ambitious and desire to advance their careers at a faster pace than previous generations. This ambition may be contributing to the increase in ageism among younger women. If they encounter rejection from an opportunity, they may attribute it to their age rather than their skills."

Thomas suggests that pairing young women with mentors and fostering a culture of intergenerational collaboration could help reduce ageism in the workplace.

Hyperproof's supportive and inclusive environment has made Chatterton the happiest she's been in her career as a senior marketing specialist.

""Those conditions make it easier to succeed," she says, as her colleagues and managers trust and listen to her."

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