Well lucky you and happy birthday, it looks Roman to me - but I am no expert on Roman coins.
It doesn’t for one minute look like it has been in the ground for 2,000 years! Take it to your local Police station they will be able to give you a reasonable valuation, maybe return it to its owner and if you identify yourself and who so kindly gave you the coin, could also recommend payment enforced by a court of law! Seriously though, nice condition Roman coins can bring €30-50, if it is a rare type more and you should take it to a reputable coin dealer. You need to search the catalog yourself to find out which coin it is, as for authenticity it is almost impossible to tell from photographs as rare ancient coins are often forged.
„If your reply or post in the Forum stinks of AI, I will call you out! Knowledge comes from experience, the I in AI stands for incompetence.“