Which song should I sing for... (please answer 10 points!)?

So for my 18th birthday tomarrow (even though it's monday) but anyway
back to the point. I'm going to an amusement park with a couple of
friends. And there's this karaoke place. And I was thinking of doing
it because I think it'll give me great practice, and I already have a
youtube channel so I was thinking of putting the video that I record
of me performing up there. But people on youtube are saying that I
have a great voice... but I'm debating which song I should sing, and I
have no idea which one to pick! So here are my top 2 choices (and
really the only 2 that I know well on the list they have):

Back to December by- Taylor Swift (I know this song really well, and I
feel like
I have a similar voice to hers)

or Kelly Clarkson's "Since U Been Gone" this song would be really fun
to sing, because it's more an energetic type of song, and it's a lot
faster than Back to December. And I can sing this one well too.
Do you think that if I put a video up of me singing either song I
could possibly get discovered if it gets a lot of hits or something
like how Greyson Chance did, or like Maria Aragon, or Tom Andrews (all
signed by Ellen DeGeneres), because my dream would be to be an actress
 singer. And I have about 18 covers up right now. So this would be my
19th :) But which song should I sing??? And how could I possibly get
discovered by doing this?? And I've been on youtube since March so
uh... yeah which one should I sing?? Oh and I DON'T WANT THIS FOR THE
FAME! AT ALL! I just want to sing!! But how could I get discovered by
doing this?? And which song should I sing?? SERIOUS ANSWERS ONLY
PLEASE :) Thanks :)