is the d7000 an old camera?

The D5100 and the D7000 are two different specification levels.  They share the same sensor, so theoretically they will produce the same image quality.

However the D7000 offers the following advantages over the D5100:

• Higher capability autofocus system;
• Higher frame rate;
• More direct external controls for common settings (as opposed to having to use menus in the D5100);
• Two memory card slots vs one
• Built in focus motor to allow auto-focus on older lenses;
• Many more customisable options;
• Larger viewfinder;
• More durable body with magnesium alloy sections and some weather sealing.

The level of sophistication and control also means you may need more time to learn how to get the best out of the D7000.

Also the body is physically larger which may or may not be an advantage for you.

The D7000 is "older" in the sense that it was released before the D5100, but it is still the current camera at that spec level in the Nikon range (although it appears that a newer version is due early in 2013) and definitely a more capable camera.