Nonprofits are required to meet specific requirements to get tax-exempt treatment before engaging in income-generating activity. 501(c)(3) status is not granted automatically (IOW, it is not granted "statutorily"). It is a legal status specifically granted by the IRS after a review.
Income raised prior to receiving the exemption is almost always treated as income earned through non-exempt (i.e., for-profit) activities. There are exceptions, of course, but you need to consult a tax lawyer (specializing in non-profit/charitable tax law) to figure out if you qualify for those exceptions. There are very important reasons behind this (including, but not limited to, the deductibility of transactions).
State tax law may be more permissive, but that only affects your state tax status. Federal tax law governs your federal tax status. It may be possible to be a non-profit for state taxation but a for-profit for federal taxation.
Also, to address inaccuracies in your blog post: 1) There are no age restrictions in any state on incorporation. However, few businesses will enter into contracts with minors unless their parents guarantee the contracts because minors have very special rights under American contract law.
2) There is no need to incorporate a solo operation. Incorporation is intended to simplify accounting for collaborative efforts. Individuals can simply register a DBA (if they're making up a "company" name"). In your case, incorporating is proper: you claim to be founding a charitable organization, so incorporation is a necessary step to receiving tax-exempt status.
3) It's humorous to see that you believe that a non-profit only needs to file 2 forms, online, once a year. Those two forms are just the start. There's a lot more paperwork involved.
You need to consult a lawyer, immediately, because you may receive a call from the IRS in the near future.