Do I speak three languages? No. Sure, English is neither of my parents’ first language. But again, they came to the US as kids, went to school here, and both speak perfect English. However, my dad does not speak Korean, and my mom doesn’t speak Greek, so we all speak English at home. I know some mixed kids grow up bilingual (and I’m jealous!), but I don’t get the trilingual expectation.
Now, my grandparents, while they understand English, tend to speak their respective languages, so I was around both growing up, and I can understand a chunk of both.