I don't know a ton about making combo videos, but I can give you some general common sense pointers and tips for the next one. First of all, unless you feel like it's absolutely vital, refrain from adding clips that are poor quality (the sets where you recorded the TV with a camcorder for instance) and 20xx clips with eye ****** color pallets. I liked the music choice, but I feel like you didn't really put that much effort into the production besides just editing all the combos you liked into one video and playing music over it. My favorite combo vids are usually all high quality clips, oftentimes with a cool intro, and bonus points for at least somewhat syncing the combos to the music. A couple of my favorites to give you an example:
600 Hours: A Young Link Combo Video and
FALCON ALL SUNDAI
600 hours is a little bare bones but the combos are so amazing it kinda doesn't matter. FALCON ALL SUNDAI is probably my favorite combo video ever right now. I've also generally heard a lot of praise for
AriqueNuubs, and I dig it because the combos are cool, but personally I think it runs too long, the music is kind of obnoxious, and they went a little bit overboard with the silly effects, especially the red flashes and random screen tilts. The other piece of advice I'd give you is to get a recording setup if you don't already have one, just a cheap one will do the trick, but just something so that you can have footage of you playing at home that's good quality. That, and give yourself some time before making another one. Some of your combos were pretty solid, but all in all the whole video was fairly lackluster and you can tell that you're getting a lot of combos on bad players that shouldn't really work. You've got a lot of potential, but I think you have a little ways to go before your matches are combo video material. Keep going strong dude, you're off to a great start, particularly for somebody who is only 15. Good luck, I hope this helps.