It can be a common factor that leads to depression. But it's such a normal feeling! I feel like that constantly at 32. I think part of that feeling stems from low self-esteem, and i've found that focusing on what i am good at, or what i can do to improve helps alleviate some of that feeling. Like, what are your strengths? What are the things you think you could do to improve what you feel stupid at?

There's always gonna be someone smarter than you, but maybe it's a good thing to be surrounded by people you can learn things from, and some people you can teach. That way you kind of balance out feeling stupid and feeling like you can really help someone else.

Hope that helps, just some things i've found useful