Gennaro, great to see you here. In response to your question, I would say it depends on your financial situation. When I was a student, all I had was a small 5 megapixel point & shoot, which at first was very limiting, but I found ways to learn a lot about photography from that little camera. If money is tight, use the point and shoot to work on composition, lighting, etc. If you have $1000-$2000 dollars to spend, then we can discuss more sophisticated alternatives. What are you working with now?
A good setup is a DSLR with medium range and wide angle lenses, at least 18mm, but you'll eventually need a nice 10 or 12 mm (Canon thumbs up, don't bother with cheap ones like Cosina, or third m like Tamron or Tokina).
For interior shots, start with using available ambient light (I wouldn't advice using any built-in flash). For better quality shots you will have to invest in a pro light system.
A tripod is a must for interiors with low light.
If you are going to do serious architectural shooting shift lenses are most important. While you can do some correction for perspective distortion in Photoshop, you loose some of the image are and you cannot reorient your shooting position as with a shift lens. Current DSLRs that us manufacturers shift lenses are Canon and Nikon. If you are using Nikon DSLR some older P.C. lenses, the 28 and 35MM are available. Both are great for interiors. If you have the money, the Nikon 24 PC-E and 45 PC-E are also great optics. They are expensive, about $1500-1800 used.