In 2018, 21 is the most common age for an American (U.S.) Aaron who is a registered male with the Social Security Administration. It is the 95th most common male first name for living U.S. citizens.
For those of you who don't like the spelling of this name, you have two options. You can drop one A, or you can add the H, for Aharon, which is the original and more accurate transliteration of the name. It really is that simple.
https://www.idescat.cat/noms/?id=115&lang=en
https://en.m.wiktionary.org/wiki/Aaron#Catalan
https://ca.m.wiktionary.org/wiki/Aaron
https://ca.m.wikipedia.org/wiki/Aaron