Why the long gaze after giving her a compliment?

I gave this lady friend a compliment on how good she looked last night (and she looked really really nice), I said it in a cute way ......anyways after that she laughed and started to blush but then she gazed at me in the eyes for at least a few seconds (felt like a hell of alot longer) to which i became flustered and excuse myself> i know i did the dorky thing of leaving but i was nervous.....why the long gaze though?