It's funny that she couldn't answer to you, why?
Its very simple.
It's always been a problem.
Doctor never told us about it because they do not learn hormone therapy in med school. One have to take a special course, as a part of continue education but because it is a very complex thing and the course cost $3-5,000 many doctors never do.
If your doctor can't answer why, she is most likely not so good with hormones and i would not trust her with prescribing me testosterone. I seen many cases when uneducated and non experienced doctor prescribe testosterone and when side effect kicks in - they don't know what to do and they let patient develop female breast or to lose bolls, I am not kidding, ask any bodybuilder, they know more about hormone therapy then most doctors.
You can ignore the fact that you low on testosterone and to age normally, nothing wrong with it. Millions of people chose to age fast and meet the end of days in no health.
Also, whatever Alphadogg16 said, also true.