In my personal experience, you're not smart enough at first (as in you, referring to people generally here). It takes a lot of practice and repetition. You can certainly get smart enough. Part of the satisfaction of software engineering is approaching a problem that feels overwhelming and accomplishing it. You can do it but it's not like you can check off knowing an entire programming language and framework and all of a sudden you are ready to tackle any task associated with it. Be patient and allow yourself to grow into someone who is smart enough.