Denise, first off, you look fabulous! Let NO ONE convince you otherwise! (And I hear you about wanting to be liked by everybody and getting occasionally a little wobbly on the confidence from there --- it's my own bane.)
With that said, since I'm hearing about this lady for the first time, I'm also going to say --- as I see it from having no Kardashian-shaped baggage either way --- I think she looks just fine in terms of age appropriateness. I *personally* would not make some of her fashion choices --- *really* skin-tight skinnies, added to lots of other on-trend items like the statement jewellery and moto jacket and leopard heels --- but that's a purely subjective judgement (apart from the fit bit). Yes, it's ALGO, but if that's the way she wants to play it, then more power to her!
I am a little leery of the whole 'age inappropriate' issue --- to me, the only obvious no-go is childishly cutesy, which I personally think doesn't suit teens any more than it suits adults. Everything else, I'm liable to agree with Victoria --- what looks 'wrong' is wrong at almost any age. If I don't want to see a glimpse of a 60-year-old's thong underwear, I'm not sure I want to see a 16-year-old's either. If there's too much boobage on display in a too-small bikini, it is *too much* at 20 as well as 80 --- it isn't that there's anything wrong with showing boob; it is that the damn thing clearly doesn't fit and you're un-stylish enough to wear something 3 sizes too small to show your boobs!
There *is* the issue of what can be worn as rebellious or ironic varying with age and era; but that's not the same as 'age appropriate'. When I wore baggy oversized shirts in pop brights and abstract and tight jeans in the 80s, it was a reaction against the 70s flares and fitted paisley silk shirts of my parents' generation from just a few years ago. My wearing it was rebellion and advertisement of my 'youth' and 'arrival' and 'newness'; my mother wearing it *would* be a case of MDAL to most people --- but I suspect it would be more about her being the wrong generation, and trying to dress 'young'. Some trends are meant as a 'breakaway' and wearing them is tricky if you've just been wearing the opposite. And me trying to wear 80s-inspired trends now requires a certain level of toning down (not as in-your-face emphatic as my preteen/teen self) or an awareness, an indication of the 'revival' that shows a wry sense of humour. In this sense, you can wear any trend and any style at any age, but you can't wear it EXACTLY the same way each time it comes around!
Final comment, from the perspective of a journalist who has hung around, entirely too long for comfort, awfully close to the tabloid-ish and sensationalist writing that this represents: This is not about her age and her clothes so much as a judgement on her life and lifestyle. And it is most emphatically not a piece written *because* of her clothes, it is only centred *around* her clothes --- seemingly. *She* is chosen possibly due to the Kardashian association; they wouldn't be saying this of Helen Mirren in a Bo Derek-esque bikini, right? They need carpy copy (Really. Am 100% serious. There is an understanding that bitchy gets eyeballs, as it equates to 'attitude' and it is hard for many less-than-stellar editors to stay within the bounds of 'entertainingly opinionated' and not stray over into 'catty for cat's sake'). They need novelty (Kardashians done to death; who's up next?). They need mainstream appeal (I may not recognize her, but I sure as heck know the Kardashians --- see how wide this net is spread? Taking any random grandma off the streets will not do it). THAT is what this article is about --- a side of the industry that revels in 'taking the high and mighty down a peg', something that was once relegated to the spirit of carnivalesque and considered bad taste and bad attitude most days, but now every day is a party!
Oof! Sorry about that. Rant over. But seriously, this article has little to do with serious dissection of age appropriateness.