My advice is don't tell him/her about your stammering because. when you tell someone or someone tell you that you have a stammering problem then you will have anxiety about how they will react to my stammering so your stammering will be worse. I'm telling you this because I've experienced this. I have had a stammering problem for the past 11 years I met 2 of my besties on twitter and we talked on the phone and we met f2f but I never stammered in front of them because I never said to them neither did they realize my stammering. But when i tell someone that i am a stammered blah blah then my stammering becomes worse.