Shutter life is rated based on previous product history for items with a similar design. I haven't seen any authoritative info on the T3i shutter life, but most of the Rebels were up to 100,000 actuations. They last a little longer because they are limited to 1/4000 sec, otherwise I'd expect a shorter life.
In reality, a shutter may die after 1 use, or last for 10 million. I wouldn't worry about it, all indications are that it might go for a million or more. The ones that were going to fail have already failed.
If the camera industry is anything like the automotive industry, any new components (or systems) which are to make it into production will be subjected to a key life test. Basically, a pass/fail standard (including cycle counts) will be predefined, and an automated test procedure designed to replicate normal usage (I guess in the case of a shutter, the odd burst at the cameras max frame rate, many single shots, and a variety of typical shutter speeds, no doubt at various predefined environmental conditions), all with enough time to allow the system to cool/settle sufficiently between cycles. This will only take a couple of weeks to test. Any failure will result in going back to the drawing board. And as the design progresses, later builds which are a closer approximation to the production model might emerge, which should be subject to the same testing procedure.
So the shutter count is just a way of quantifying what the shutter is designed, engineered and tested to. It's a typical usage minimum, not a maximum.
Or, read this to get an idea how long your shutter could last: http://petapixel.com/2012/12/22/look-up-your-cameras-lifespan-with-the-shutter-life-expectancy-database/