Nobody wants to be looked somehow because of their age, but it is popular practice to see women reduce their age. The 3 views below are of the writers and its interesting read.

1.
I think because we live in a culture and society that values youth more than age, more so in women. A female goes through at least three distinct stages in her life, that of a child, a maiden, and matron. The peak in a woman's life if typically the maiden period in that they are young but considered women. It is like that sweet spot where they have that youth and beauty that men desire, and therefore men value women in this period more.

When she was a child she lived underneath her father's household, as a matron she is under her husbands care, but as a maiden she in theory has at least some control over where she goes after that.

When a woman is in that maiden phase, it is relatively short in relation to the rest of her life. Like ten years at best? And inevitably the woman will age out of this maiden period, and then more assumptions and expectations are piled on.

After the maiden age range, a woman is expected to be a mother and to be ferrying kids to soccer practice, and needs to get home to cook the meal for her family, people stop viewing her in the context of an individual but in the context of a family.

And I can imagine having people hearing your age, and automatically placing you in this context can be frustrating. Assuming that you are married, but if you aren't that you want to get married desperately, that you have kids, but if you don't, you want them desperately.

I read a critique of statistics of how hard it is for women to get married. Pretty much a lot of single fear mongering goes something like this: "It is harder to find a partner for A demographic, X% of A women are unmarried at the age of Y!". However, they never factored in the possibility that they were women who didn't want to get married at all. If I am 35 and single, it isn't because I "couldn't find a man", it is because I didn't want to get married. But people would automatically put me in the pitiful box, and that I must have tried really hard to get married only to fail.

But because of age there are so many assumptions are piled on a woman. So as a way to circumvent it a bit, women might lie about their age.

2.
When I was younger, I used to tell myself I wasn't gonna be the type of person who lied about my age. But you know what? I've done it a few times, and more than a few times I've implied that I was younger than I am.

The times I've outright lied about it were on dating websites, for the reason the Anon gay man mentioned. I believe the first time I joined a dating website, I was around 19, and I believe I told the truth that time. But the second time I tried it, I was over 25, and was advised to put my age down as less than 22 because many people's search criteria stop at that number.

Didn't believe it, but when I experimented with age 39 vs. 40, I probably got about 10 times the attention (winks, emails etc.). No fooling. The hits I did get as a 40-year-old tended to be guys in their 50s and 60s. As a 19-year-old, I got many more hits from guys around my age, which I what I wanted.

Ok, that's dating. But I've also implied a younger age in professional and social settings. I work in advertising, and it seems like a lot of it is aimed at younger people (age 18 to 25 seems to be the most common demographic). I worry that people (potential clients, especially) may feel that I cannot relate to younger people, or that I am not up on the latest music, art, pop culture etc. that is basically required for someone in my profession.

I am also one of the oldest people, by far, in my social circle. Off the top of my head, my closest pals are 24, 22, 23 (three of them) and 25. Thank god my BF is my age (he's actually a year older, LOL); I also am close to my siblings (ages 24 and 21 (twins). I'm xyrs, BTW. Did I forget to mention this? Anyway, my buddies know how old I am, but they do say they think of me as younger, and I must admit I encourage this perception. And being unmarried and childless helps in this perception; my life experience is closer to theirs in a lot of ways.

I do play the "age card" sometimes, but it's not something I necessarily brag about. I suppose vanity has a part in it, but it's a small part. For me, it's more about fitting in, socially and professionally.

3.
I'm going to answer for myself, personally. It has to do with two factors, 1) why don't women like revealing their age and 2) why don't people like revealing their age.

1) For many people, everything changes when you know a woman's age. How you judge her appearance, assess her career accomplishments, look at her personal life. It gives you a yardstick to measure someone against. It happens to men, too but not as intensely.

The most common comment I hear in the circles I travel in now after someone finds out a woman's age are

-"She doesn't look her age" {Sounds like a compliment but means, "I didn't know she was THAT old!" Can also mean "I think she's had botox"}

-"She doesn't look too bad for her age" {Eh, at that age, you shouldn't expect much}

-"Her age really shows" (Means, "I kind of guessed she was that old, but I didn't quite believe it. She should have botox."}

This phenomenon is particularly acute for women after 35 years of age because that is when you become keenly aware of your body changing in small and irritating ways that you have little control over. But that's another question.

2) The world is divided into those who are older than you and those who are younger than you. Those who are older, God bless them, are usually polite and look with fondness at the years when they were your age.

On the other hand, those who are younger frequently have not accepted the fact that they, too, are getting older. Finding a gray hair is the end of the world. It's like they think they can freeze their life at 27 years.

They frequently distance themselves from people 10-20 years older (between their age and their parents), I think because they represents domesticity, settling down, maybe compromising with your career because, damn it, real life often interrupts our plans. Unlike previous generations who eagerly embraced adulthood, many Gen Xers, Gen Yers and Millennials seem to, somehow, think they will be spared, everything in their life plan will work out but due to the miracle of science, their minds and bodies will not experience aging.

It is very painful for me to listen to 20something describe someone as young as 35 in disparaging terms because of their age. It shows a naiveté and insensitivity that is remarkable in people I find smart in so many other ways. I wish I could tell them, "You, too, will become your parents."