Its a difficult thing - deciding whether to tell people or not. You're under enough stress with dealing with the situation, you don't need naysayers and fearmongers crawling up your....leg.
If you feel obligated to tell them, I'd wait until the last minute - that way they don't have time to weigh on you about it. Let them know you've done your research, made your decision and its a topic not open for discussion or negative comments - and stick by that! They may have questions, which is normal, but you can answer those questions with an email or showing them a website.
Bottom line, you know your body better than anyone and you've decided what your body needs. Good luck!