I am a young 20 something, right out of college, first time startup founder, developer and with almost zero business knowledge guy. It's hard to accept the truth you are saying, but I am learning.
Just make sure you can tie everything you do to your customer's needs. If you find yourself thinking about technology for technology's sake (e.g. "let's rewrite in Scala" or "We need a 12-tier system to manage scalability) (for you curtsy user...)), start worrying.
Fortunately, there is an easy cure: go talk to customers. Your good customers (or potential customers) will point you the right way.
