I don't believe in love at first sight in fact I'm kinda iffy on that "love" but considering the question, I think you get a crush on someone at first sight and then after getting to know them better you fall in "love" with that someone
I don't know about love. But infatuation sure. I liked a woman named Tara, and still do after several years (4 years last met). Never asked her out even when she gave me all the signs, since I wasn't ready.
Personally, I can't fall in love at first sight. Initially , a guys appearance attracts me, but it's his personality that I fall in love with. So I need to know a guys personality traits , qualities and values before I would reserve a place in my heart for him, and fall in love