Mario, it's common in the United States for beginning backpackers to buy a lot of equipment, and then as they gain experience --- find that they don't like so very much the gear that they bought. What's common then is to pare down some, both in the amount and type of gear/clothing carried. In that context, a common recommendation is to buy the backpack as late as possible. Rent or borrow a pack if possible, or at worst buy something fairly cheap (perhaps used) to use in order to get some experience.
I think that it would help this group interact with you if we had an idea of the kind of backpacking that you're interested in --- what general areas, what time(s) of year, how long a trip in miles/kilometres or days, anything you can tell us about what you're interested in doing.
The only backpacking that I've done in Italy was a few days along the Via Francigena in Tuscany --- "backpacking" but sleeping each night in ostelli or hotels, so not quite the same thing! :-)
Your enthusiasm is clear --- best wishes for good equipment choices and great trips to come.