Am I just not smart and should I just give up even trying?

I wouldn't necessarily say your stupid..not everyone is good at school, i mean I used to get straight A's in middle school and now in high school I kind of struggle. But honestly I don't think doing bad in school necessarily means your stupid, you could be really handy with tools, and school didn't teach you that. So I wouldn't say your stupid everyone works at their own pace, and school doesn't teach you everything.