First, are you male or female?
Males, if they are going to experience schizophrenia, normally do anywhere between the ages of 16 and 25, and females between the ages of 25 and 35.
Have you done research on the disorder to find out if your symptoms match? If you can't talk to the doctor, write everything down and bring it in.
You are very young to have this debilitating brain disorder. Are either of your parents schizophrenic? If not, you only have a 1% chance of getting it. If one of your parents does, you have a 13% chance, and if both parents have it you hit a 35% chance of getting the illness.
The racing thoughts and pounding heart sounds like a typical anxiety/panic attack, however those are quite different from each other. A panic attack is when you fear impending doom. Anxiety is when you are anxious and nervous, you may sweat, rock back and forth, hold your chest, get shortness of breath, etc. Like butterflies in your stomach and you can't get a thought processed.
If nothing else, a prescription for an anti-anxiety agent might be what you need. You either take them everyday no matter what, or only when you have an attack.
Either way, you MUST see your doctor. Are your parents understanding? If one of them has the illness, they should understand, though they may forget how bad it can be initially and how scary it can be so don't be upset if they don't get it. Most people don't get it. That's why we are such a unique set of people. We have one of many illnesses that ALMOST NO ONE understands. Physical conditions are easier. We can see them. Yes you have a broken leg, I can see it. Let's put a cast on it and you'll get better. But when it's a mental condition, then what? We can't do brain scans to check on the chemicals and see if they are working properly. We have to go on feelings and emotions and medications are more of a trial and error approach until you feel better.
Having said that, several people have taken a keen interest in mental health, so do some research. There is a lot of good reading material out there. A lot of professionals are previous sufferers as well. Who else would understand us so well?
Good luck and keep us posted on what the outcome is!!!