Hi there,
I've been in Marketing for 12 years now, the last 10 in Procter & Gamble. In parallel I've created 3 startups, so my opinion is the following. While you will learn tactics by working directly in startups, you will have a faster learning of strategy and consumer driven design and marketing in large corporate companies, such as P&G or Unilever. That is the kind of marketing that doesn't fade away. After ~3-4 years, consider if you still like corporate or if you are ready to start your business/work in a startup. If you do, you'll have learned in Corporate not only marketing, but also acquired the structure and discipline needed in any future business you might want to work in (or launch).

Now, while rewards of working in corporate are high, succeeding in Corporate is not an easy task. You can learn more on wolfleaders.com or reach out directly to me on Clarity.

Take care,
Serena