From what I’ve heard, schizoid personality (as well as all schizo- spectrum) has a strong genetic component. But it is debatable whether this genetic predisposition could manifest anywhere on the spectrum depending on a various events in person’s life experience. 

Meaning, one might be schizoid from birth, but will they get a fully manifested schizoid PD, schizotypal PD, schizophrenia, etc... or maybe they’ll be just “high-functioning” (don’t quite like this term, but for the lack of a better one) schizoid or schizotypal without any disorder. That will depend on something along the way through their childhood, up to 20-something. 

I’m trying to say, according to this theory it’d be possible that what you describe could lead you to having a schizoid personality disorder. But for that you’d have to be somewhere on the spectrum to begin with, i.e. to have this genetic component. But of course I wouldn’t bet this theory is 100% accurate. 

Vocal range test engaged:

"Do Re Mi Fa So La Ti Do"

"Do Ti La So Fa Mi Re"

Well. at least I know that still works.