Overthinking about a Letter

I wrote a super, super important letter to my crush who I literally cannot reach otherwise and who is also almost never home recently. The mailbox last names are scratched out outside so I checked inside and I THINK it was the fourth to last, I know I put it in the fourth to last mailbox but now I don't know with 100% certainty if his mailbox was actually the fourth the last. Like if I maybe saw it wrong while checking or I miscounted and messed up. The issue is I didn't write his last name on the letter itself, I didn't think it was necessary if I deliver it personally. But now if it's wrong then the person receiving it won't even know who it's meant for. And now if there's no reply I'll keep wondering if he just didn't reply or if he never even received it.