Batman Begins took place in 2005.
The Dark Knight took place in 2008.
TDKR took place in 2012.
Dates shouldn't be of any concern.
It's not one large world. Unless of course Gotham somehow changes from looking like a model built, studio constructed, CGI enhanced Chicago (Batman Begins), to the very heart and soul of Chicago (The Dark Knight), to Pittsburgh, LA and New York (TDKR). A city just doesn't change in look with three, completely different cities, skylines, etc. in the span of a decade. Unless Gotham tore down it's miles and miles and miles of buildings and replaced them.
There's also the fact that Wayne Tower changes as well. Why would such a prominent building in Gotham first look like the Chicago Board of Trade building, to a Chicago building, to New York's Trump tower? That's a pretty significant change in architecture, not to mention the applied science division. It's pretty cramped and claustrophobic in Begins (save for the Tumbler test room), but the ones later all vary to a degree.
Then let's not forget little Jimmy Gordon. A kid doesn't just grow from a toddler being spoon fed (in Begins) to a 10 year old (The Dark Knight) in just under a year.
How about Rachel Dawes? That must have been some pretty crazy plastic surgery she underwent to go from looking like this,
In, again, just under a year.
Speaking of which. Why would Bruce Wayne have a picture of Rachel Dawes in TDKR . . . from when they went and had dinner with Natasha and Dent at the restaurant!?! She's not even looking at a camera. Why would there be a pic of Rachel, wooing over Dent at a restaurant?
How about Wayne Manor and building it "brick for brick"? Wayne Manor in TDKR doesn't even look like the one from Begins. In fact, the foundation surrounding it is completely different as well! How does the foundation and land just completely change around the Palisides? Even the interior doesn't look the same. Even the entrance from the outside of the Batcave's waterfall to the opposite cliff isn't the same area.
So in Batman Begins' reality, Selina Kyle isn't 16 or 20. She doesn't even exist. How old is she in The Dark Knight? Nada. She was born sometime in 2011 and was revealed to film audiences everywhere on July 20th, 2012.