Hello,
If the weight and size you gave are correct : no doubt it's fake.
See here and compare :
https://www.acsearch.info/search.html?term=caesar+denarius+elephant&category=1-2&en=1&de=1&fr=1&it=1&es=1&ot=1&images=1&thesaurus=1&order=0¤cy=usd&company=
The republican denarii (even late) are not supposed to make less than 3.5-3.6g. If it's a bit less, it's maybe because it's a fourree. Here it's obviously not, it's far too low.
Diameter is too small as well (it should be 17-20mm).
Moreover, the planchet is a bit weird for a denarii, the shape and the rim are strange. Looks like they are made to make the coin look old and authentic, but it does not look so.
Finally, the surfaces are not as they are supposed to be. They look cast. The cast-look can also be seen on the top of the sprinkler and on the letters.
Sorry about that, I hope you did not pay too much for that coin and/or you can return it to the seller.
This denarius is not rare at all (it's actually a very common one), but due to the high demand of Caesar's coins, its price is usually several hundreds. It's probably the most faked denarius also. When you buy this coin (especially when you spend some money into it and you expect it to be authentic), I can only recommend to buy from a trusted dealer or auction house or from someone you know to be a serious collector.