Career Advice - PhD/Fed/IB...

I'm currently a junior at a top LAC and will be interning this coming summer in investment banking.

I've been thinking a lot about my longterm career goals.  Like many on this forum, I always wanted to go into finance and IB seemed the best route.  I am very excited for this summer and think IB is a great path, but I've become intrigued by the idea of getting a PhD and working on macroeconomic research.  Macro has been my favorite coursework in school and I love following the Fed.  I am also very interested in capital markets, asset pricing, and that whole space as well and I am a math major (one reason IB is becoming less compelling to me as it seems the work at the analyst level isn't that intellectually stimulating).

The general consensus seems to be not to get a PhD unless you want to go into academia.  I know PhD programs are long and rigorous but I think I would really enjoy it, but I also don't want to be out of the workforce (especially if I convert IB this summer) immediately after college and feel like working for the Fed or being an economist for a HF is more exciting than being a professor. 

My questions are:

• When is the best time in your life to get a PhD? (As in the best time to be out of the work force, regardless of the state of the economy and outside factors you can't control)
• For anyone on this forum that has gotten a PhD - Was it worth it?
  • It seems like many of the most influential macroeconomic policymakers worked in finance (IIRC Powell is the first Fed chair to have been in IB, but there are many throughout the system)
• How early do I need to be serious about applying to programs?
• Do interesting jobs that exist at the intersection of economics, finance, and mathematics exist?

Overall: What career path advice would you give to a current junior interning in IB who is passionate about macroeconomics and economic research but also interested in careers in finance?