You're reading too much into this, most likely! It's not like she's saying "the love of my life".
Everyone had a first love, that doesn't mean we still love them now! however, they will always hold a special place for us, because, well....they were out first love!
Maybe you could tell her in a nice way that it makes you feel a bit awkward, but really, I don't think there is anything wrong with it. Unless she mentions him at every opportunity, of course, in which case it would indicate she is not over him.