Turning 35 today is a very different experience for most young women, compared to their mothers. Firstly, they are still considered "young women", whereas their Baby Boomer parents had probably resigned themselves to middle age by this point. Thirty-five might be when women are told their fertility "drops off a cliff" but it's also the age at which researchers say we peak - becoming more confident and happier.


It's why we think the Duchess of Cambridge should embrace her 35th birthday. But that's not to say she shouldn't be a realist. By the middle of their fourth decade, most women have learned a few valuable life lessons - and realised what was best left in their twenties.


1. It's too late to persuade people to use your full name


Your birth certificate might say Catherine, Genevieve or Henrietta, but if everyone's been calling you Toots since nursery, trying to upgrade to your full name just looks like a desperate attempt to appear grown up.


Still with the shortened version or affectionate nickname - though that doesn't mean it's OK for your spouse to call you 'the missus'.


2. You have a public alcohol limit


Quick wine after work? Sipping fizz alongside foreign dignitaries? The days of drinking without consequence are over. Keep tabs and chug water - the hangover just isn't worth it. Not to mention the gnawing feeling that you asked the Canadian ambassador whether he was on Tinder.


3. There's no such thing as a grown-up


We're all just big kids play-acting at adult life. Behind closed doors, it's tears, tantrums and toys (just the expensive digital kind these days).


4. There is a ladylike way to sit


And it's called the "slant". Legs together, ankles crossed. Knees superglued. Wear your biggest knickers, just in case the paparazzi turn out.


5. You can't get away with not flossing


The gaps between your teeth are catching up with those in your memory.


6. Eye-rolling is fun


Just the right side of bitchy, sending your eyes skywards can also be interpreted as affectionate. It's the perfect conspiratorial move - especially when spending time with the in-laws. Perfect your eye roll, but don't deploy it too often - making enemies after 35 is exhausting.


7. You know the value of older friends


Gone are the days when you surrounded yourself solely with peers. Now, you've cultivated meaningful relationships across the generations, as well as having a mentor for brutally honest guidance and plenty of eye-rolling.


8. Cheap wine is not for you


There was a time when plopping ice cubes into a vinegary white at Mahiki meant you could get it down without having to hold your nose. That time has passed and your head, as well as your tastebuds, will let you know it.


9. You buy clothes in multiples


Found that perfect dress? Suddenly, you're compelled to purchase it in every colour. Remember when that beloved pair of jeans frayed in 2003? You're not going to make that mistake again. See specifically: underwear, Uniqlo heattech, polo neck jumpers.


10. You've stopped saying sorry


Over-apologising is seen as a female trait- there are even courses dedicated to stamping it out. By 35, you're at least aware of doing out and can catch yourself before saying sorry when someone else spills your cups of tea. On the flip side, you know how to grovel when it's really needed and aren't too proud to admit when you were wrong.