Developed a crush on another woman.

I have been straight all my life and I’m even married with a child. I have recently noticed that I developed a bit of a crush with another woman. She is lesbian and married to a woman. Of course I will not take any action on this crush but it’s the first time I have ever had a crush on a woman before. I noticed I get a bit of butterflies when she is about to come in the room. Has anyone else developed feelings for the same gender for the first time as an adult? Why is this?