Is it normal that i always felt like i looked similar to my bf's sister?

So when I first saw her, I was like wow, she looks like she could be related to me but my boyfriend never said that about me. I know that'd be weird but still. I then just assumed it was all in my head and that I somehow just thought she looked like me. His sister sorta said she saw a resemblance when I said don't we look like sisters as a joke once but that was it. Then tonight my parents meet her and both of them look at each other and say "My goodness you look like a twin of our daughter!" I started laughing because I felt that all along. We have the same color hair, slightly similar eyes, same exact shaped face, same weight, same sized nose, similar smile, etc. She also dresses like me and always has.

Then after she left, my parents asked "did you notice anything unusual about her?" They both said I looked just like her.

is it normal no one on his side of the family sees this? Even his own mother never said anything about this.