Could there be something mentally wrong with this person?

So I met this girl and she very very bubbly and pretty. She is always happy to the point where its creepy. Her personality comes off as an act, but I think she is actually like that. She does very well in school. She knows exactly what she wants to do after high school and has known since she was in the 6th grade. I went on a four hour rode trip with her and the whole ride she would not let me sleep she kept talking and talking to me. If i would try to sleep she would poke me. If I ignored her and pretended to be asleep she would still talk. I think she likes me, but everyone says shes very promiscuous. Its her over happiness and hyperness that leads me to believe she is not 100% sane. Like she always happy no matter what happens.