At your age do not I reapeat do not self medicate.
Discuss this with your doctor, it can be treated.
Most Gyno in your age group does go away if not there are many differant cause for it that need to be properly assessed I will let your doctor discuss that with you as I do not by any means want to frighten you.
My geuss is it will go away in time but most certainly needs to be addressed by your doctor.
If in the event it needs surgical correction while any invasive surgical procedure should be taken seriously this type of procedure can be done out patient meanning you will go home the same day after resting at the hospital.
Again because at this point you do not have a accurate diagnosis for why you have gyno.
And your inability to be able to monitor blood work hormone levels etc.
You do not need to even entertain taking any medication by yourself you can wind up in a world of trouble or make the situation worse.
I might also add as embarrassing as you may consider this I strongly urge you to speak to your parent and honestly tell them how concerened you are and how bad it makes you feel.
I am a father and beleive it or not we as parents Love you very much and will be more understanding than you may think. Plus because of your age you will need a Adult to Champion your cause anyway.
Heres a Tip you may need to be evaluated by an Endocrinaologist.
Good Luck and all the Best to you!