Tanjiro and you had been planning to spend Halloween together, so he was fixing his werewolf costume, when you walked in excited about the fact that it's Halloween...

It was at that moment that you mentioned going trick-or-treating. Hearing this, Tanjiro looked at you...

"Aren't you too old to be trick-or-treating?"

He asked somewhat confused, after all he didn't expect you to have planned to go trick-or-treating with him before the costume party...