When personal and business money share an account, you never actually know what the business earns, because every figure has your groceries mixed into it. You end up guessing, and guessing tends to be optimistic.
Two accounts means the business balance is a real number you can act on, and it turns bookkeeping from archaeology into arithmetic. Do it before the first payment comes in — it is a twenty-minute job at the start and a miserable one later.
Speak to an accountant about how you should pay yourself out of it. That part is worth proper advice.