Why?

I don't remember it happening so soon. With Javi, I'm pretty positive he was at least four before I had to answer my first string of never ending, relentless questioning.

Why, mama?

Me: It's time to take a rest.
Bella: I don't wanna take a rest!
Me: Sorry, monk. It's time.
Bella: Why it's time?
Me: Because you've been up a long time and you need some rest.
Bella: Why do I need some rest?
Me: Because you've been up a while.
Bella: Why have I been up a while?
Me: Because you woke up a long time ago.
Bella: Why did I wake up a long time ago?
Me: Because the sun was up.
Bella: Why was the sun up?
Me: Because night time was over.
Bella: Why was night time over?
Me: Because that's the way the world works.
Bella: Why is that the way the world works?
Me: GOOD NIGHT!
Bella: WHY IS IT GOOD NIGHT?

Seriously? She's not even three yet. I know she's very verbal and is the type of child who searches to understand things in a way her brother didn't. I'm aware of that. But I'm still in the thick of Why? with the older kid -- surely I'm not already saddled with yet another bout of Why? I don't think I can handle it.

I wonder how long it'll take me to cut her off after two Why?s like I do Javi:

Me: You need to go brush your teeth.
Javi: Why do I have to brush my teeth? We're not even going anywhere!
Me: Because I said go brush your teeth.
Javi: But why?!
Me: Because I am your mother and I said it and therefore I want it done NOW. 
Javi: FINE!

I also have to wonder how long it'll take for me to reach my mental capacity. I can't remember what the line of questioning was, but I once had to admit to Javi, "I just don't know. That's why you should stay in school, so you can be smarter than your mom." 

Why, me?!