It depends on you. But i would guess, it´s more or less about 2 years. :)

Human beings do their best to defy any truth that could be obtained via statistical methods, especially when knowledge or moral qualities are the subject. This simple fact is both sad and happy.

It's up to you, how many hours are you planning to spend here on italki? :) 2 years more or less and you can reach c1 lev. if you take lessons and get a good italian grammar book. Cheers, D.

How long? everyone's different! ;) The more passion and effort you put into it, the faster you'll learn ;)