Announcing pregnancy- dealing with negativity

Hi everyone,
My husband and I are 34 and recently got our BFP :) We're really excited, but haven't told anyone (except for Glow 😊). We'd like to wait until the first trimester is over, and while we think most people will be happy for us, how would you deal with someone's negativity or rude remarks ? 
I'm just thinking about this, because of our age, and how to announce to people who might be sensitive or rude ?
Backstory :
 When my brother and his wife announced they were having a baby at 37 most family was happy and supportive, but one person told me to my face that they were crazy. She wasn't joking, and went on about how crazy they were. I simply reminded her that was my brother she was talking about and that I was happy for them and supportive.
Another example, my sister is in her early 30's and would like to have another child . The same person told her not to, because she's too old and it would be too hard on her health. When I asked what was wrong with her health, this person said 'I think she's just too old' . 
Also, I have a few friends who don't have children for different reasons . One is having fertility problems, one isn't in a relationship, but wants children and sensitive about it, and the other is also not in a relationship and has literally told me she doesn't like children ( She just told me that one day. I didn't ask ). How can I tell them gently ? I'm not sure how they'll react . 
Thank you everyone 😊