I live about 30 miles west of Lake Michigan; from about the second week of march into about last Thursday, we had a warmer (not considerably warmer, mind you) than normal weather, with enough rain so that we didn’t have to water a lot but not so much that the ground squished under our boots. All of my maples and many of my other deciduous had begun to leaf out before temps dropped to highs of about 30. That was last Thursday. Mine have been in the shed or garage since then and today I brought them out, but I’ll be doing the two-step on and off the next few days.
5 days in shipping would put your order date probably right around or a bit before last Thursday. Your tree 100% has been shocked in your cooler New England weather. Bad news, those leaves are gone, as the above folks have said. Good news, looks like the 10-day forecast by you up there in Salem, NH (thanks for updating your location, you witch-burner…. JK
)will be just warm enough to put it out and leave it out, with the exception of Saturday/Sunday night. Keep it watered and once you solidly have temps above 45 at night and there pretty much no more chance of frost, begin to *lightly* fertilize it. Emphasis on lightly. No need to blast it right away, most of what you put it runs thru the drain holes anyway. If it responds well maybe in June bump it up but don’t hit the gas too soon.
Seems like it’s at least 4 or 5 years old, maples grow relatively fast, possibly less if it’s been in the ground since it was a wee lil one. That means it should have enough energy to get itself going again, but as someone above said, don’t go messing with it this year. As willing as you are, anything beyond water and easy feeding is a bad idea.
Trust me, I know how badly you wanna get in there to “save the tree”. We have all had that feeling when we started.
And every single one of us has murdered numerous plants as well. You seem to have passion just based on your posts. If you do lose this tree (I give it 70/30 it makes next May; if it does you’re fine) don’t get discouraged. Find some books, do some research, join a club. Pretty sure if you search “New England bonsai club” in the search bar of this forum you’ll find a dozen leads.