I'm not saying You should believe in "love at first sight." Heck I'm not saying what You should believe in at all. I will ask a question though - what of love at first sight did exist, and all You are doing in not believing in it is stopping that joy from reaching You?
I believe love takes habitual work. I also believe that it makes most of the work seem nothing like work when it is love. Whether I believe in "love at first sight or not" is for me to know. What I will share is that I believe in love's magical power - I've seen it work too powerfully to not believe in it.
Any time our souls meet a soul which ignites us, that is something to be explored. Cautiously but not fearfully. Fear blocks joy. Now, our souls cannot truthfully express themselves without self work which must come from self love. Only after we align ourselves can we feel love's excitement. Whether on first sight or a few sights after that.