Is it normal i can't stop thinking about a girl?

This isn't your regular obsession. I saw her 1 day in kindergarten (yeah, laugh it up), and instantly got weird feelings, ones that I couldn't properly process. These feelings persisted consistently until 5th grade (that's when everyone started pairing off). I realized that I definitely wanted to date her, scared of rejection I never got the chance, because, halfway through the year she moved away. Also I don't have a facebook (long story), so I haven't seen/heard from her in 6 years. But I can't stop thinking about her. I've had girlfriends, but while I'm with them all I can think about is her. I'm honestly concerned that I'll end up a stalker or something, because I should be over her by now, I've tried everything to get over her and nothing is working. I hate to use the word 'love' because 90% of the people who use it, misuse it, but I can't describe it any other way. I guess what I'm trying to ask is: is it normal to always miss your 1st crush?