At some point everyone has to learn to stand up for themselves, Its better to start now, it will save a lot of headaches. The culture of the JWs make people think they have a right and responsibility to judge and tell you what to do. It is up to you to manage this. The less said the better, so practice a few things to say when this happens. A shrug, downcast eyes and "
" I'm sorry but I am unable to give my talk"
Why?
"I just don't feel up to it, I am so sorry"
What is wrong, are you sick?
I'm sorry, I appreciate your concern, but I can't really talk about it. I promise I will let you know when I am able to do talks again."
Then hang up or walk away.
Other possibilities:
"I am just under so much pressure right now."
"I really wish I didn't have to cancel, but it can't be helped"
Come up with something that feels right to you, practice in the mirror until it becomes automatic.
Remember, these people mean well, but their main concern is keeping you in line, which is not in your best interests, so do not feel you owe them anything. Be polite, don't lie, but don't say anything more than you have to. It's OK to simply not respond to rude questions. Or say "I can't believe you said that". Or, " I'll pray about that". Some people have developed the art of placating others without actually giving any real information. My Son was a genius at it.
You have a right to think what you want, even if you are young.