Let me share some hacks for you -
Be financially independent : Once you start earning well for yourself, the world starts taking you seriously. If you’re dependent on your parents’ money for survival, the world won’t be too kind to you.
Find your tribe : Easy to do in this age. Build a Youtube channel, blog, podcast series or an Instagram page. Once you’ve even 100 people who resonate with you, your opinions will be taken seriously.
Start speaking : Good public speakers are taken seriously worldwide, no exceptions. Worth spending time on developing this skill.
Become exceptional : If you are a CA, become a great one. If you are a designer, make world-class designs. Aiming for perfection leads to great work. Great work leads to credibility.
Get stamping : Get into IIT, IIM, Stanford, Harvard or other such prestigious institutes. A lot of people would take you seriously just on the basis of your credentials.
Create something : Art, business, music, garden - just build anything you feel really passionate about. The world respects builders and people who add value to the world.
Another way out is being a stoic. If you don’t care what the world thinks of you, you don’t need any external validation. However, for a lot of young people, validation is the most important thing. As you become mature/established, it’s easy to rise above all these things.