What a great way to get into Nikon, with a D7100, the best Crop sensor camera available, and joining the Nikonian's community. Welcome to the group, Serge. The D7100 is a lot of camera with many features that can be overwhelming at first but there is enough expertise collected so far on this camera by other members that any questions you might have will be sure to get a good answer quickly.
I have the D7000 and remember when it came out, a lot of people were surprised by the steep learning curve. But the D7100, with even higher resolution, seems to be adapted to quicker without the initial problems of technique, focus and exposure questions. Stan St Petersburg Russia