Why is my new iPhone sending iMessages from my e-mail instead of my number?

I got a new iPhone for Christmas and when I tried sending a message to my friend, she said it came up as my e-mail. My number is selected but when I unselect the e-mail, I can't send messages.

Try to change the setting in you imessage go to SETTING-iMessage-Send & Receive-Then uncheck your email address so everyhing will be start and receive in your number.

IMessage is emailing.
I've tried, it is like I'm'ing but by email.