[bootload]

"... I am currently looking for and seeking a technical co-founder for a new music start-up I am working on. ..."

Age isn't the problem here, understanding the problem domain is.

"... This year makes me 18 years old...An ideal co-founder for me would have to be no more than 2-3 years older than me, because most older people may not be very comfortable working with side-to-side with someone of my age. ..."

I think the idea of a co-founder and age being incompatible has less to do with age than perceived and actual competence and power. Competence because it's difficult to work with idiots. Power, because an in-balance of power regardless of age turns working with anyone into a master/serf relationship.