The same video that Brett White gave for my question: How old is Bruce Wayne at the start of the New 52? also answers this question.
According to this video interview conducted by iFanboy with current Batman writer Scott Snyder, he is between 31-35 in Batman, which takes place in the modern day New 52 Universe.
From the video:
The writers aren't too concerned with the timeline. Because Batman could potentially be as old as 35 he could have been with Talia when he first started operating as Batman (circa Year One) at the age of 25.
While he has only been publicly visible as Batman for 5 years or so, he has been operating as Batman since he was 25. So somewhere between 6-10 years.