Please explain the psychological term "first effect", thank you very much!

The first cause and effect, for a simple example, you dated a beautiful MM, and you were deeply moved by her the first time you met her. After the second and third meeting, she was not as impressed with you as the first time! This is the influence of the first cause effect, which means that the first impression often leaves a deep impression on people. Of course, there is another person named "recency effect". This is the latest one. Literally, you can guess about the same.