Is it normal that i've had an old acquaintance on my mind?

Someone I used to talk to almost every day on the bus ride to and from school 7+ years ago recently came up in my mind, and I've been thinking a lot about them since. We liked to talk to each other and were friendly, but never hung out or got very close. We lost contact after high school several years ago and haven't really seen each other since with the exception of bumping into each other a couple of times within the first year out of high school. I have no idea why I thought of them, but I have been wondering what they are up to these days and missing our chats suddenly. I've had other former classmates bring up memories of this person in the past and had brief thoughts about them every once in awhile, so this isn't the first thought in years or anything, but it usually goes away after awhile and is not this time.