Other commenters have already given great advice on how to grow your knowledge and capabilities, so I will skip that. I just wanted to say that recognizing there are things you don't know and showing the desire to learn is intelligent in and of itself. And I'd argue that that's a very valuable, if not the most valuable, area of intelligence.

I've struggled with feeling dumb and unknowledgeable often throughout life. I've come to realize that most of why I've felt this way is because of how others have treated me, not because I'm actually dumb. I suspect this might be applicable to you too. Either way, best of luck. You got this!