How long afterward did your doctor recommend surgery? I'm in my early 40's, and was diagnosed today. New glasses will help for a time (about a year, the doc says), but I will be having surgery eventually. I guess I'd just prefer to have it over and done with while I'm relatively young and in good health. I'd love to drive at night again instead of relying on my husband. So, my question is, if you've had posterior subcapsular cataracts, how long did it take you to have the surgery after you were diagnosed?

Not had, but as an optometrist, had to deal with.

Posterior subcapsular cataracts tend to be more disturbing of eyesight in their early stages than other types of cataract, and often develop fairly quickly.
(only the sclerotic cataracts tend to move faster)

The relatively good news is that you no longer have to wait until they're "ripe", which used to be the case.
Surgery can be done at any time, as soon as the inconvenience of the vision impairment* outweighs the inconvenience of the operation, and the (small) risk of having it done. But as you say, the operation is likely to be needed at some point anyway.

The additional point at your age is that the operation will remove any remaining natural ability of your eyes to refocus for near, and although the distance Rx can usually be re-set near to zero, you will be faced with choosing between using reading glasses or varifocals for reading, or opting for multifocal implants. This a a personal choice as, although the multifocal implants offer great flexibility to many, there can be compromises with best vision quality and, once again, problems with night-time glare.

*if the problem is day-time or night-time glare, the actual letter-chart vision can still be quite good, but the problem still be large enough to prompt surgery.

I had cataracts develop rather quickly just over a year ago. In my bad eye they could not correct my vision to any better than 20/80 so I went ahead with surgery and an implant for that eye.

I chose multifocal and was pretty happy with the result. Three months later the other cataract had worsened so I had the same surgery and same type of lens for it. I was extremely happy with that result after going in the next morning to find I had 20/20 vision in that eye, 20/40 in the first one.

However, a few weeks later I began to notice an increase in the number of floaters in both eyes but, especially in my 20/20 eye. Back to the eye Doctor I went and was told I had developed numerous vitreous detachments in both eyes. My eye doctor said nothing could be done about them and I asked for a second opinion.

Off I went to a Retina Specialist and he said pretty much the same thing. I'm at the point now, a year later, where I have a very hard time reading even in bright sunlight and have had to purchase a much larger monitor for my computer and sit very close to it to be able to read.

I'm not trying to scare you, just make sure you ask questions about what can go wrong and listen to what they tell you. Ask questions and think about if you can deal with not being able to read, or possibly having more surgery for a detached retina, which is also a possible complication of cataract surgery.

Your situation is probably different from mine. I was extremely nearsighted and I am 10 years older than you.

I hope everything goes well for you. Good luck.