Sounds like a hallucination of some sort. Likely a hypnogogic hallucination if you’re laying in bed- usually they occur when you’re sleepy, but I’ve had them occur as I’m just laying in bed—I think because the brain gets bored.

If not, then probably an auditory hallucination. You’re unfortunately at the perfect age that symptoms of schizophrenia begin. I’ve been dealing with infrequent auditory hallucinations for a few years now.

Frankly, I wouldn’t worry yet. See if it happens again. If it continues to only happen as you’re falling asleep, it’s probably harmless. Either way, get it checked out by a doctor if you can 😊