"i'll keep Aki a secret for now" i don't really understand this sentence, someone explain ...

It just meant "i'll keep it a secret from my parents that i'm dating Aki,"
Atleast thats what i think

Oh i see... At first, I also thought like that too but- the way he speaking (by himself) to his parent. As if his parent know. This is just my assume.

I think there is meant to be a kind of cut from where he was talking to his parents and talking to himself