Relax, you're only 15! You know, there are other ways to get noticed, and this way probably isn't the best. I'm not sure what genre of music you want to concentrate on if not classical, but here are a few things that might help you get noticed from where you're at now:
1. Start from the top. It's great that you've won some competitions, but if you want to take your playing (and your all important resume) farther, stay away from regional, very small competitions. They can be even more corrupt and self serving than some high power, well established ones. Larger scale, international competitions with broad repertoire reqiurements are worth entering if only to get more experience, and to highten your chances of being in the spotlight.
2. If you feel you are ready, and have a good amount of substantal works under your belt, you might want your teacher to contact an agent or manager. The magazine Musical America (in bookstores and libraries) has vast agent listings (as well as comprehensive competition listings). Despite what people think, it's not always a bad thing to be proactive and take the straightforward approach in the musical world. Discuss with your teacher the possibility of calling up a local listing and explaining what you have to offer. It might result in an audtion. Agents love young talent. The worst that can happen is that he/she might say no.
3. Perform at any and all chances you get, even if it's just at student recitals. And, if you have the means, rent out a cheap space to give a full scale concert, or a debut if you will.
5. Attend masterclasses ( for a small fee at conservatories, music schools, etc.) with teachers other than your own, and make contact with other musicians in chamber groups, so that you can perform more.
4 Talk to your piano teacher openly about your problem. Teachers usually have the best advice, understanding and sympathy for such matters.
5. The main thing is, you have so much time to get noticed that you shouldn't rush anything. It will just make you frustrated and hate the piano (the worst possible thing). You are at the perfect age for entering so many "young artist" type competitions, doing concerts, attending masterclasses...etc. So don't worry. If you don't want to embark on a classical career, (you seem a little bored with playing only classical) it's a whole other ballgame, so if you haven't already, explore other pianistic genres, there are so many. But while you're deciding, listen to the great piano masters, find a composer(s) that you adore, and take joy in simply making music, not so much playing for the sake of competitive progress. You'll be happier if you do.
Good luck!