Bossy only child?

My four year old is getting increasingly bossy and I realized that since he's an only child he's just mirroring back the way we talk to him when he's not listening. For example at bedtime we only have time for two books but he wants to read five.Me: Okay we are going to read two books, can you please go pick out two books to read?Him: I want five booksMe: Sorry bud, we don't have time. Do you want to read [this book or that book he liked last night]?Him: No, five booksMe: I wish we could do five books but we only have time for two books. Do you want to pick or should mommy pick? (aka pick some books or else I will)He looks me square in the face and starts copying behavior/posture I'm sure he's picking up from his teacher at school: No, you. not. listening. Turn on listening ears. I say five books.Then I have to say two books or no books, he may or may not make a whole Thing out of it depending on tired he is. If we try saying that mommy and daddy are grown ups he says he's a grown up too. At day care there's obviously the teachers and the students and at home we try to let him make as many decisions as he can ("this shirt or that one" type stuff) but he's trying to figure out how far his authority goes (answer: not as far as he'd like). If he had siblings I think it'd be easier to say "Mommy and Daddy are adults, you and [sibling] are kids. See? Your sibling doesn't get to do [whatever thing] either because that's a grown up decision."Is this just something we have to ride out? Is there a way we can get through it quicker? I know it's developmentally normal, but I'm tired of it already. We happened to pick up a Fancy Nancy book that mentioned her being bossy about making her family be more eco-conscious so we were able to use that as a way to talk about it, any other book suggestions or conversation topics would be appreciated. via /r/Parenting https://ift.tt/2Zrr8zL