My girlfriend is overly scared\emotional all the time. What to do?

I’ve been with my girlfriend for four months. She has a great personality and gets along with everyone. She loves me with all her heart, but sometimes I think it’s just too much. What I’m worried about is that her being overly emotional and scared is going to drive me away. What I perceive to be very irrational things tend to make her scared or upset. If I’m not there to comfort her she will cry to me. She was raised very sheltered. Examples are:

*Movies with mild violence. While watching “The taking of Pelham 123” she almost cried and needed to be comforted the whole movie. She was upset afterward for over an hour.

*She hates that I smoke (weed). Although she claims shes cool with it she will get upset just seeing it it my room. Out of respect I don’t do it around her, but I feel theres no need to make a big deal if you just see it

*Me doing mildly risky things such as lighting off big fireworks. She was really scared for me to the point where I had to comfort her for some time.

*She can’t sleep without this bear she had since she was 7.

I don’t know how to describe it but she just demands a lot emotional attention and comforting. Were in our 20s and I don’t think she should be scared of everything. A girl who is scared of life is not attractive to me. When i call her out on things she just gets upset and says that’s the way she is. How can I talk to her about this issue?