Great advice Birdie. I agree with writing things down at home where she feels safe and then taking it to her counselor.
There is a teenage section on MedHel that you might find is better for your needs than this community. However that is up to you and I am not trying to dissuade you from posting here. However, we are not professional counsellors, and even if we were could not help much from here.
Your doctor is providing good advice. Your feelings need to be brought out in the open so a helpful therapist can give you some advice, but only you can make that decision. Otherwise you may suffer all your life with problems that you are capable of overcoming, but just didn't have the right tools shown to you.
Start writing down right now everything that you feel, make an appointment and take it all to the meeting. That is part of the honesty that you need to bring to the therapist, and it may be much easier to submit paper than to speak about it. If you just try to say it in front of them, you might get embarrassed and hold back important facts.
With a full picture in front of them, it is much easier to study your situation than if you keep coming back over weeks with little bits coming out each time.