I wouldn't do it ASAP.
I would do it as soon as you comfortably can. Refinancing means you lose a lot of protection towards your loans. It also means the clock to repay back your loan starts ticking a lot faster ( if you want good rates).
If you are planning to build a practice, you would want to remain in a loan repayment program as long as you can to free up cash. Once you get a stable and high income, then move to refinancing. Otherwise you will be tied down to a job with poor growth but you can't leave because you gotta make those big repayments.