Yes it can be a symptom of BPD, but that doesn't automatically mean you have the disorder. Being impulsive and taking risks can also be a natural part of being a teenager. Self diagnosing can be dangerous and can cause added anxiety. Remember just because you fit a few symptoms doesn't automatically mean you have the disease. If you're really worried about your behavior, the best course of action is to have a talk with your doctor about it. Be honest, explain how you're feeling, and what you think it might be. If they themselves can't help you, they can usually point you in the direction of someone who can.
Whilst it's true that impulsivity is a diagnostic symptom of BPD, it doesn't necessarily mean you have BPD. According to the Diagnostic and Statistical Manual of Mental disorders volume 5 an individual needs to meet 5 or more of the diagnostic criteria for there to be any worry of having the disorder. If you are concerned however that you may have the disorder checking in with a medical professional is always a good idea to consider. Impulsivity can be an extremely scary thing to have to deal with, but remember that there are many support avenues available to you, and that your wellbeing matters.