My friends learn constantly, and I want to do so.
For what reason have you chosen to learn new things?
My friends have always criticized me for being too dumb
I can see where you come from, and I think it is understandable that you want to do things with your friends. You should improve yourself but you should do it for your own sake, not to impress your friends. Otherwise you will be just satisficing them which is bad.
Mostly, I just want my friends to stop criticizing me.
I think it's great that you have friends that have encouraged you to educate yourself more. Comparing yourself to them isn't good, but learning more is.