I'm skeptical about needing a Guru for spiritual growth. Does the text provide any examples of someone who started with this skepticism?

Yes, the text directly addresses this perspective through the personal story of the author, Annasaheb. The preface, referencing his own account from the third chapter, reveals that he initially had no Guru devotion at all. He was a skeptic who believed making a Guru was a 'fraud' and felt there was no need for one, taking great pride in his own capabilities. As chapter 0 describes, this deep-seated skepticism was completely dismantled after his first encounter with Baba. The experience left him fully convinced that one cannot cross the ocean of life without a Sadguru, making his journey a prime example of a skeptic's transformation.