Can someone give me some advice please?

[Why?]

When I was in high school, in my science class, there was a girl who always looked at me (I'm also a girl). I never approached her because I was too shy. But after I graduated, I came across her twitter and saw my name in one of her tweets with a <3 next to it. Now its been 2 years already and I still think about her. I'm thinking of sending her a message on facebook to see how she's doing but I don't know exactly what to say? I'm thinking of messaging her on Christmas so I have something to tell her. I just regret not getting to know her because I would never know what could have been. Please help me with what I should say. Thanks