"Success" as a twenty something

Ahhhhhh early 20s. So far you have been an absolute rollercoaster. What is it about being a twenty something that everything feels so life and death? 

Why is success only measured by what you achieve by 30? When did 30 get all this pressure and hype because I didn't get the memo. Here I am, in my last year of college with all of the possibilities at a hands reach and yet I am more concerned with this abstract idea of success. And achieving something insurmountable in a socially acceptable amount of time.