Unlike mosttop-level domains (TLDs), .ITdomains only allow you to register 1 year at a time. For this reason, you can't renew your .IT domain more than 1 year out from its expiration date and .IT domains can only be renewed if set to auto-renew or explicitly renewed after the actual expiry date.
Please note that registration date won't change until the current expiry date is up and the domain auto-renews.