Sure, you can go work at ________ (big company paying fresh developers $120k+), but you're going to be pigeonholed into working on a small aspect of the product/company.
If you join a promising small startup, you're going to learn about all aspects of business, startups, selling, marketing, fundraising, etc. These skills will be extremely helpful to you throughout the rest of your career, especially if you plan to start your own company someday.