I would not be too concerned with the matter of using first person and third person singular tenses. Substance is the issue. However, the overwhelming majority of business plans are written in the third person singular, referring to the company, not a person. It reflects a sense of formality and normal business practice influenced by legal mores over time.
You are better advised to make your decision on the relationship between you and the banker of record. On the other hand, if this document is intended as a plan for a company that will hire a workforce you may be better advised to implement third person singular and refer to the company name. If and when the document becomes a matter of record in the business venture, partners and employees allowed to read it will view it as a perspective on the business concern, not the ownership.
I hope that makes sense to you.