Does everyone get cataracts? Well yes... if you live long enough. You see, cataracts are an ageing process of the crystalline lens of the eye that happens in everyone. And it begins from the moment you are born till the day you need a cataract operation.
As the crystalline lens ages, it loses both elasticity and transparency. We are born with about 20 dioptres of power of what's called accommodation or focusing power in our lens and by the time we are 60, it's pretty much zero. That's why most people need reading glasses at about 45- by 45 we lack the zooming power to focus on objects closer than our arm's length.
Your lens is also generally more opaque at 45 than it used to be, so you are not quite as sharp as you were when were 20. However, the opaqueness doesn't get bad enough to be called a cataract generally you are about 60 plus. Of course, there are certain things that can make it more likely you will get cataract earlier such as diabetes, sun exposure and if you are highly myopic or short sighted. And again there are some people who don't get cataract till their 80s and 90s even. For example, the Queen of England only had cataract surgery recently and she is 93!
The good news, of course, is that cataract is one of the most fixable of the conditions we get as we get older. And the technology is getting better all the time.