Having already done a few rides exceeding 200 km before, I've just made it official by completing my first a 200 km brevet two weeks ago, with BC Randonneurs (Canada). I was hoping that by waiting until June, the weather would be more favourable, but no, it ended up raining on and off all day.
The nice thing about randonneuring is that since you're all competing together against the clock, the incentive is to cooperate with anyone who seems to be going at a similar speed as yourself, and after 100 km, you will likely soon discover whose ability matches yours the best. I ended up partnering up with a veteran Super Randonneur and finishing the course together, which I found to be an extremely satisfying result. Apparently, it was good enough that people started asking when I would do a 300 km brevet. (Unfortunately, I already have plans to keep myself busy for the next few weeks, and by August everything will be put on hold for Paris-Brest-Paris, after which there's not much left on the events calendar.)