Right approach, wrong execution. You were trying to pass the shit test, but you did it wrong. "Yea" comes off weird and won't cut it. You should have said "Yes.." or "Absolutely" or even just "Yes". But "yea" doesn't convey the same high-value confidence that is needed to pass the shit test. There's a reason behind every text, learn to understand WHY a text works rather than finding "good" texts to use.

Since when did she leave you on read ?
What do you think she is supposed to respond to ''yea'', try putting yourself in her shoes, you wouldn't know what to say either.