At your age and level, I would personally just go with some simple linear periodization using 80% of your max.
Build a base in both muscle and technique before you start going into 90+ percentages.
Go with a simple 5x5 scheme. When you can 5 sets of 5 reps bump the weight up 5lbs then rinse and repeat. If you want to gauge your progress, it probably wouldn't hurt to go for a hard triple once a month. Leave a rep or two in the tank at this time in your training for that hard triple. Don't push any sets to total failure. That is, never miss a rep. If you have to leave 1-2 reps in the tank to insure that, that's okay.
If that sounds like it'll bore you to tears, then have a day where you do like above, then a day where you do the same thing but 5x3 with 85%, and 5x2 at 90%. If you can't do it, just keep working at it till you can.
When you stall, take a break for a week using 50% of your estimated max.
When that no longer works, then after the break take 90% of your estimated max and use that as your training max that you come up with your working weights.
When that doesn't work, go with weekly progress, then monthly, then find a real program.
Simple is all that you need right now and you'll set yourself up for the most long term gains and fastest beginner gains by milking simple for all it's worth.
When you're more proficient with the lift, ramping up to a set to near failure will make more sense. For this conversation I'd call near failure a lift you can't do for any more reps, but can do just a little more weight.
I can tell you one thing, if all you do is train upper body losing fat may very well be a hellacious venture. Chicks dig nice legs and a butt too fyi. Yeah, they look. Yeah, they can tell.
I honestly doubt 14 yo me would listen to what I'm saying now haha, but I think if you do you'll be in a much better place than I was.