Would it be weird if I messaged a girl now?

[Charlie]

Basically, there is this girl that really like from my church. I usually see her once or twice a week and we talk a bit - not lots though. I have never chatted to her on Facebook before however I really want to, to be honest. She liked my latest status update.. Would it be weird for me to randomly message her and, if not, what should I say? I'm not the best at starting conversations. Should I only msg her when she is online? If it was you, what exactly would you say?
Thankyou in advance

Extra information:
She wasn't at church yesterday so I'm guessing she is on holiday.
I think she likes me a bit because she looks at me differently to other girls, we both have the same favourite animal, she knows I love guitar and she plays flute, I'm a year older and I wouldn't call myself popular at school, I am, I think, a bit more at church though. I don't have her number atm , how could I get that because is it weird to ask her this late?
Thanks for reading my essay! haha

[Brandon]

I would ask her "Why weren't you at church yesterday?" doing this shows that you care about her and is a good way to start a conversation with her, without being creepy.

[Shivam adhvaryu]

Look buddy you can msg her whenever you want to so just msg her anything if you don't know just say when do you come online mostly & she will reply.. & if she really likes you then she'll start the conversation

[Jazlyn]

Yes you should message her, To start it off just be lke "Hey I'm kinda bored What youd doing?" and then it goes on from there

[awefxs]

Why not answer? Just say "hi."You will show your love no matter what you say. The point is just say it.

[Jack]

Just message her about anything you two share interests in this should make the conversation flow better, best of luck. Can anyone answer mine http://uk.answers.yahoo.com/question/index?qid=20140216020424AAcQTn0

[Candie]

Not at all. Go get her. Online or not. Just start with a simple hey