I am guessing that you are searching for the rare 1990 no "S" proof cent. First of all, your coin doesn't look like it's a proof. One thing to remember, is that only a few hundred were released by the mint and these were only found in Proof sets. The mint sold approx. 3 million proof sets so that's roughly 0.01% of 1990 sets may have a No S cent. It is unusual to find Proof coins in circulation. I have been collecting and searching my change for over 45 years and in that time, I only found 2 Proof coins (of any date) in circulation. In order for ANY proof coin to be found in circulation, someone would need to break open a sealed proof set and then spend the coins. Even though a lot of proof sets have a low value, they nearly always can be sold for a few dollars over face value, so spending them is not very common. It does happen, but not very often. In order to find a 1990 No S Proof Cent in change, it would require that someone actually had one of the 0.01% of the sets that contained the error. Then that person would have to be one of the very few people that would go through the effort to break open the set and spend it at face value. Then out of the billions of cents currently in circulation, you would have to be lucky enough to find it. Just like winning the lotto, probability says it's not going to happen to you. Hope this helps. It's too bad the You Tube videos don't explain all of the details
When you live in a high population area you have better chance of finding some ones cast off coins in circulation. That goes for proofs as well anything out of the ordinary, keep hunting.
