Would it be awkward if I called the girl I like on her cellphone?

[Arthur]

I had one of the best days ever at school today. I was sitting in my 3rd period class minding my own business and everyone was sitting by their friends and talking to each other because it was the last day of school and I'm one of those guys that are shy, friendly, and caring. So then one of my guy friends said What's up Arthur why are you sitting all alone and not talking to anyone and I said I don't know and my friend said hey why don't you talk to those group of girls right there and I said I don't think they want to talk to me and he said sure they do all the girls in this class like you and I'm all like how can you tell that I see the signs they give you. So then guess what my friend does he asks one of the girls from the group and says hey can Arthur join your group and talk to you girls and then she asks me is that true you want to talk with us and I said yes and I thanked my friend for hooking me up with the group of girls. I started talking to the group of girls that were all beautiful and I felt like I was in heaven they started asking me questions about my personal life and one of the questions was have you ever had a girlfriend and I said no and then she asked me another question and said do you like any girls in this school and I said yes and then she said what's her name. I was feeling nervous around the group of girls so I didn't say her name out loud so then she told me to write her name on a piece of paper and give it to her and I said okay. I wrote her name on the piece of paper and gave it to her and she read it and said Aww that's so cute your first crush you have good tastes in girls and I said yeah she's really beautiful and popular and then she said do you talk with her and I said yes were good friends with each other and then I said but to bad she's with someone and she said who cares if she is with someone you derserve her better than her current boyfriend and then she said I have her phone number you want her phone number and I said yes and she gave me the girl I like her phone number and she said here you go your early Christmas present and then I said thank you. So my question is would it be awkward if I called the girl I like on her cellphone? And what should I say if she says how did you get my phone number?