I really really like this person, but there is an age gap and i dont think i have a chance, what can i do?

I really have began a random crush on someone who i dont speak to and have an age gap with. Maybe its just a temp. thing but i really think i like them. However, i have them on facebook but cant muster up the courage to speak to them or wouldnt know what to say. They probably dont even know i exist, but to me there on my mind alot lately. What can i do? anyone had any similar experiences?