Um... I honestly don't know very well how to answer this. I was in therapy for a year and a half before getting on T... but it had nothing to do with being trans. In fact, I never even mentioned to my therapist that I might be trans until our last appointment. A year and a half or so later, I went to a doctor (regular old M.D.) who specialized in trans issues, and she prescribed me T without any prerequisite but a blood test. I was a special case, however; I had been married for a year, to someone who identifies and lives fully as female, and had personally identified and lived fully as male for over a year. She told me if she'd had any question that I was unsure about transition, she never would have prescribed it in the first place.
I don't know how that will affect me when and if I ever have the means to pay for top surgery. I'm hoping that the fact I've been on T for so long will be sufficient for any surgeon, but if not, I suppose I'll figure things out at that point, and enter therapy if necessary.
Asher, with your being only 16, I don't believe there's any possible way a doctor would prescribe testosterone without your being in therapy and having a therapist's recommendation, as well as parental permission. As other guys have said, it's quite tempting to take the easy way, to order testosterone online or what have you, but it's honestly best undertaken with a doctor's help. Without the blood tests and regular check-ups, you could cause yourself greater health problems down the line. There's a reason most guys go through the motions, regardless of how mundane or irrelevant they may seem: it's just the safest course of action, in the end.
SD