Why won't my iPhone let me use my email?

I tried to add my email address to my new iPhone earlier.

I put it my name, email address and password, but it says,'The username or password for pop3.live.com is incorrect.'

(I have no idea what pop3.live.com is)

My email address is correct because I have used it for years prior to today, and my password is correct because I checked it on my email on a computer recently and it worked!

So why won't it work now?!

My cousin keeps copying me, what do I do?

Okay, to make this clear I'm 14 1/2 & She's 12.
By the way, all the stuff about 'she looks up to you' is not true in any shape or form.

Okay so when I was about nine, I liked 'Hello Kitty' this was a big thing around my age group and my friends knew I liked it. I was given HK presents and stuff.
As soon as I knew it, my cousin started to copy me, she'd buy everything that I had.

Then when I was 10, One Direction was (and still is!) my favourite band. I got loads of 1D stuff and obviously I didn't tell her because I didn't want her copying me. Then she pretends to be this massive fan and wants to buy all their merch.

It frankly does annoy me. But that's not the worst of it.

I've always loved these two youtubers called Dan & Phil (Danisnotonfire & AmazingPhil)
As soon as she knew I liked them, she 'liked' them as well. She was writing Dan & Phil all over her arms and began to watch all of their videos.

I love Muse too & Thomas Sanders (from vine) and that's gotten to the point where she decided to copy me for that too.

Then I got BBM for iPhone and I tend to put 'Dan&Phil' in my name; i don't know why.
She copied that too.
When I put up dp's (display pictures) of Dan&Phil, she copies them, especially the ones I made myself and puts them as hers.

She won't be original and thinks it's hilarious to copy me for everything in which it isn't. She won't get any originality.

I tried talking about it to her but then she goes off in this massive mood and calls me really mean things that no 14 year old girl would want to hear from their 12 year old cousin.

She pretends like she doesn't copy me when she really does.

I don't know what to do anymore.

What means iPhone is flashed to Sprint?

So I'm buying iPhone 5C from eBay and it says: "Bad ESN (which mean that it can't be activated on Sprint) and flashed to Sprint" my question is: What means "flashed to sprint"?

How to save up for an iPhone 4S when you're a teenager?

I got around $120 total for my birthday if that helps start… And I'm not looking for a brand new one just a used one. What are quick ways to save money? I really want one but my mom can't afford it.

BQ: Is it better to just save up for a new one instead of getting a used one?

Added (1). "get a job" that's what I was afraid of hearing, Nova. Plus I'm 14 what jobs are there for 14 year olds

Iphone beta app won't delete?

I recently downloaded an app that is not through the app store and is in beta. It uses a username and password to be installed which were given to me by the creator. I decided the app wasn't for me and deleted it. Then the next time i unlocked my phone the window asking for the username and password for installation popped up again. I hit cancel and the app reappeared on my phone. I've tried multiple times to delete it via the phone and even another few times through itunes. I've tried turning the phone off and on but nothing works. I absolutely can't delete it! Not to mention my phones battery has been draining significantly faster since i first downloaded the app. What should i do? Do i need to completely restore my phone?