but for me...what should i do?
Hey man, it's kind of funny, as far as stats are concerned, you're exactly like me when i was 16 (three years ago), about that time back then, i managed to dunk for the first time ever in my warmups before a game. But, looking at what you been doing, we are almost exactly the same. See, i did Air Alert for 11 weeks myself and it kinda helped, did some easy strength training too which helped with my two foot jump even though i was a 1 foot jumper. However, i feel like i can help you succeed where i got stuck for a long time.
To me, it's pretty clear, you need jumping volume. That is, jumping often. The only thing is that, from experience, i know that kids your shape usually tend to develop knee problems from running jumps. So strength training remains a good expense to ensure that you do not get injured. Still, we don't want you to come even close to screwing up your natural reflexive ability that's usually good at your age. Thus, i would recommend you get in the gym 2-3 x a week working just one exercise, which is gonna be kind of a pre-hab exercise for you, all-in-one: The Overhead Squat. Perform 2-3 sets of 8-10 reps depending on how you feel. Works the shoulders, back, proper hip and knee function and the lesser weight will allow your legs to remain fresh and springy for your more important work: actual running jumps.
So basically, whenever you get in the gym, warm-up either with jump rope for 3-5 min, then make sure your ROM is good with High knees, butt kicks, lateral shuffle, skips and whatever to ensure that you're loosened up. Takes about 10 min total, make sure you break a sweat before with the jump rope.
Then, you just go and jump. At first, take short run-ups (3-steps) to make sure you're comfortable, but once it gets easy, start your run from even farther (3 point line), run and jump. Jump off 1 And off 2. Just about everyday. If your 1-leg jump feels uncomfortable 1 day, jump mostly from the other leg. (Yes, practice the other leg!!!) and when it just doesn't feel good, practice 2-foot jumps. Bottom line, you need to jump. A lot. The specificity will allow you to zero in on your goal: jumping higher, and better coordination. The Overhead Squat will ensure you strengthen the right muscles.
So to sum up:
4-5 days a week: Warm-Up, 10 min
Jumps in sets of 3-5, take a 2 minutes break, and go at it again. Stop whenever you feel pain, discomfort or your jumps get lower. Always start with the jumps that feel better (either the 1-leg jump or 2-foot jump, but make sure you do both). You should come close to 50 total running jumps per day, and 250 per week.
2-3 days per week: Get in the gym and perform 2-3 sets of Overhead Squats x 8-10 reps. Start with the bar, add weight in 5 lbs increment as you get more confortable. Add-in other exercises if you want (pull-ups, push-ups, but really it's not necessary, the running jumps will be enough stress for your legs.)
It doesn't really matter if you squat on the same day or whaever, just go ahead and jump. Make sure to warm-up!!!!!!!!!!!!
Get after it, and don't complicate it further. Stick at it for the rest of the school year. This summer, i promise your jumps are gonna be 10x better, and you'll be able to benefit a lot more from more excruciating training. Above all, enjoy it, this is the fun part of your jump training career. Now go ahead and make that jumpman name your nickname in real life!!!