Growing up, it was very clear to me how people will doubt whatever you're doing if it's even slightly unfamiliar for them, If you're doing something they don't quite understand or have no background about.
The challenging part is; the closest people can doubt you the most, and it feels really bad. But, people looking from outside they can only see one thing; results.
Results are never instantaneous, they take time, they require lots of trials, and they're never that significant at the beginning, but over time they accumulate, and they start becoming evident to everyone.
For your peers; it's very difficult for them to admit your achievements or progress, and it's much easier for them to criticize and point out the shortcomings, this can have a lot of reasons including jealousy, envy, lack of self-confidence, etc.
But again, once the achievements start being very evident, it's hard for anyone to deny them. The best advice I can give you is; never wait for people's validation or applause, you don't need other people to be convinced that you're a successful character, in fact the best thing you can do is to keep your progress and achievements private, away from the eyes of everyone.
When you keep your progress to yourself, no one will get you down through negative criticism, no one will doubt you or whatever you're doing, and the most important part is; you won't be afraid of failing.
Often in life we only fear failure because we don't want to fail in front of everyone else, we don't want to be asked about the last project we were working on and have to say something like: it didn't work.
You no longer rely on people's motivation, validation or applause, you keep it a secret till it has some fruits, because success is crafted in the moments of silence when no one is watching.
Give it a try and promise yourself you won't say a thing about a specific goal or plan that you have to anyone else, see how life-changing it is for yourself, and enjoy a hustling process away from your friends, family and social media.