I am surprised nobody replied, but welcome to PB!
As a hint, it would be best to say hello here, then post specific questions in targeted discussions to get a better response.

It sounds like a fun project, but since that area holds water part of the year, I would worry there is some sort of wetlands restrictions on its use. Is it a natural vernal pond? I would make sure you do some research on this area to be sure it is OK to dig there, or the fines and trouble you could get into can be pretty damaging.

Another note: you need some pretty large machinery to make a hole that size, and it wont happen in your lifetime with a single excavator.

I would recommend talking to some local landscapers or garden shops to make connections with excavating businesses who have successfully dug ponds in your area. Get some estimates and choose the contractor that has both a reasonable price, and who knows what they are doing. Don't go for cheapest quote. In this business, cheap does not equal a non-leaking pond. Many of us are here because we swap stories on our battle with leaks.

Good luck and sorry for the late response!