Probably yes.  Charities that are not hospitals, churches or schools generally have to obtain a broad range of public support to qualify as public charities rather than private foundations.  They automatically qualify if they obtain 33 1/3% qualified public support under the test for “donative” charities under Section 509(a)(1) or the test for fee for service “commercial” charities under Section 509(a)(2).  (See Ready Reference Page:  “Calculating Public Support Percentage.”)
The 509(a)(1) test is more flexible because it allows an organization to qualify with as little as 10% public support under the so-called “facts and circumstances” test if it is seeking to attract public support, its board is broadly representative of the public, and its services are available to the general public.  Nothing in the Regulations suggests a time limit on qualification under the facts and circumstances test, and many community foundations that receive a substantial part of their annual income from investments continue to qualify with significantly less than one-third public support.
If the other 70% of your income comes from a single donor on a regular basis, the IRS might give you some difficulty, but we have had clients qualify for many years with less than 20% public support under the 509(a)(1) test.