iybyu, I don’t think its shallow. Attraction is a part of marriage and if you don’t think you can be attracted to her, its not for you.
A bit of advice though? My sister went out with a guy and when he walked in I thought he was really ugly and squashed looking. She dating him a few times but it just wasn’t right. Then she set him up with her friend and they ended up getting married. After getting to know him a bit more, his looks got better and better.
If you can’t find a “real” reason (like hashkafa or something), I recommend a few more dates to see. I don’t think 2 dates truly does it. I would recommend 4-5 if you are hashkafically similiar and are having a nice time with her.