General

I would also like tips from people, I started to gain and it will very soon be notiveable that there's a round belly under my shirt.

Gains are usually slow so don't worry too much about what people say.
Many friends won't say anything if you gain weight some will but just own it and say yeah I guess I have gained a few pounds.
As long as you don't act like its a big deal it won't be.

If you worry about what people think or say, then perhaps gaining is not for you. You are also under no obligation to talk about it to family, friends or strangers. You can mention that you are happy at your current weight. If they keep bringing it up, you can tell them you don't want to discuss it. If they keep it up, you can leave. Obviously that will not work with family if you still live at home.

My Mom didn't like it when I told her I gained weight on purpose. She got over it in time.
She gets on me about being fat still to this day.

My Mom is a New Yorker she is loud and can be very rude so I tell her to zip it.
She means well but it doesn't sound like it to people that don't know her,LOL

I have been shamed before, I then told the that I kind of liked it. That then takes the momentum out of there shaming, and they don't know what to say but agree.

Good points Conan.
You have to be comfy in who you are and not care what others think.
I gained really slow so friends and family besides my Mom said very little about my weight.
As I kept gaining it really wasn't an issue because I never made it one.
If someone said OMG you got fat I would say yeah it does look that way.
That pretty much changes the subject matter of the conversation because they see I am not phased by what they said.

Its the people that go out of their way to say mean things are just insecure about themselves.
I used to wear a tank top that said "yeah I know I am fat you don't need to tell me".

Don't be afraid of others if you want to gain do it.
You don't tell them what they can and cannot do so why would you let them do that to you?

You are 32 years old.
Old enough to make your own decisions.
Eat more when you are not at home might help.
Personally I would not worry what your parents say because you are not a child.