Hi Luca,
Looking at those images I'd be pretty happy that it's genuine. There are no obvious casting marks, the wear appears even and natural and the cracking is common on coins of the period.
Tiberius ruled from Ad14-37, so any point in this period is fair game for minting coins.
You can see a similar example Here.
Hi Luca
First off I'd just like to say i cannot help you with saying if it's geniune or not. What you would need to do is find out the weight of a geniune coin and weigh your one and see how they tally up.
If it is a geniune coin it would of been minted around 18 AD.
Looking around on this site it looks like a group 3 coin i think. Have a good look around on that website as somewhere on there will be weights for them i think.
Stu.
Tribute Penny