Re: would leaving the stern light on all night kill my battery?
Leaving a boat moored at anchor is never a good idea. Not just for the boat itself, but for the occupants as well. If you think you might die, you need to think it through a lot more before you do it. Dying is never an option.
Leaving a boat beached is never a good idea. Mostly because it will hurt the boat. Paint on the hull notwithstanding, just don't do it.
I got my first boat when I was a teenager as well. I HAD to have one, but had no money, so my Grandpa helped me build one. I didn't try to do it all in one year. The motor was added the second year, convertible top the third, etc. I was lucky in that my Dad helped as well. Every time I got a new motor, depthfinder, etc., etc. Grandpa came along for the first ride to check it out.
That was over 40 years ago. Grandpa still watches over me from above, but sadly he doesn't get the first ride any more. Now, my kids are into boating and I help them along the way.
If you have a Dad, or Grandpa, or Uncle to help you, please take good advice and let them help. If not, please find a local neignbor that can mentor you.
You need mentoring! Listen to reason! The guys on this forum are here to help you and have your best interests at heart. Don't try to do everything in one year. Learn as you go., and go slowly. Take the boating course before you ever put the boat in the water.
God bless and be safe.