Aside from a couple of Anglican chants my first shot was at secondary school. The schools had music on the curriculum offering instrumental tuition on borrowed instruments. Among those a "music set" emerged and within that an ensemble. I wrote a set of small songs for it, sung by a boy with a very high soprano voice and good at non-tonal harmony. I don't know who influenced me - probably Berg with his 7 early Songs.
Point is, mostly forgotten now, all but two of those scores lost, the timbre of the voice stayed with me and about a dozen of my things include either a coloratura or mezzo soprano, no matter who might had influenced me otherwise.
Harder to work out how and why it happened.