When do messages mirror to iwatch?

Yesterday I was speaking with a friend threw text on my iPhone and I was 2hrs away from my house and was talking about a gift I’m getting my wife for Christmas. After I was done talking to her about it I deleted the text. Today I get home and put my phone to charge next to my iwatch and see all the messages I sent yesterday on the iwatch. We’re those messages being sent to the iwatch as I was texting even though I wasn’t connected to iwatch? When do the messages send to iwatch? When you connect back to iwatch? I’m just concerned because i don’t know if she saw or read them off my watch while I was gone.