Welcome to Coin Community, pepeole. I've removed your posted email for your own protection - this forum is very efficiently indexed by Google which would make your email quite easily harvested by miscreants searching Google for posted emails.
Very nice images. Your coin is a San Francisco issue, shown by the "S" mint mark at the lower left of the reverse. This makes it a very scarce issue - only 66,000 were minted - and worth a rather considerable premium as a result. The lack of mint luster in the images is concerning, but it could well be an artifact of the imaging process, so we'll put that feature aside for the moment.
I see nothing otherwise which alarms me regarding its' authenticity, but that is a very real concern with coins such as these. They are popularly counterfeited. Ensure first that the coin's dimensions are appropriate - 26.8mm and 16.7gm.
One feature which might discourage some is, to me, an encouraging sign: the "crack" visible in the broad area of the obverse field at lower left. This is caused by an improperly-prepared die "sinking" during the minting process, and unlikely to be duplicated by a counterfeiter.
So. Let us assume this coin is real (more on that in a minute). It is, due to possible weakness of the reverse strike, very difficult to choose between Mint State and having seen just a very little circulation. If we are to assume the worst, and it has barely circulated, you can expect its' value to be well over US$3000 (melt value is about US$600, to give you an idea of the premium). If Mint State, that value reaches skyward very quickly.
However, if you are to some day realize this coin's potential, it is imperative that you have it professionally authenticated and graded. A buyer seeking a coin of this value will not be interested in an example which hasn't been examined by a professional. My recommendation to you would be to make arrangements to have the coin sent to PCGS in Paris. You can find details at
http://www.pcgseurope.com. For some odd reason, even though that site is available in six languages, Spanish is not one of them.
Further, your best option for liquidation - should that be your choice - is one of the large American auction houses who command a broad audience of collectors/investors. Arrangements for such a consignment are easily made; they're experienced in dealing with sellers from across the world.