Hello and welcome to the Forum.
From the details given by you, it appears that you have had pubertal development which might (or might not) have stopped half way through the process. You have mentioned about the penis size and not deepening of voice. Of these, the size you have mentioned is in no way fitting into the biometrics of a prepubertal boy. If you want to confirm what the medical science believes, read from the following link a doctor's opinion regarding size of penis :
The penis also may look small if you have an obese body.
Secondly, the deepening of voice as remar has remarked in some cases may be due to a problem with the vocal cord and need not be related to pubertal development.
How was your other body developments ?, like growth spurt ( how tall are you ) pubic hair and especially testicular development ? Do you feel that your testicles got shrunk any time after its growth?
Did you have any of the following issues during your growth period?
- any inflammatory disease of the intestine like celiac disease, leading to malabsorption of of nutrients?
- Any disease like mumps that could affect genital growth
- Any wasting diseases like TB
If answer to any of the above is yes, then that can lead to reduced body growth .
In any case, as you have mentioned and as remarked by the doctor a hormone intervention during puberty would have had better results than now.
This is not to imply that it could not help you now, it may as well kick start a bit of growth process which would be helpful, however small it may be. And even your present penis size is not that small to be worried about. Also if any of the above diseases exists as of now, treatment of the disease will make a major difference to your health.
Since you seem to be having low hormone status ( by the way how much was your T level ?), you may also consult an Endocrinologist to have a full hormone level tested to ensure that the low T is not due to some large variations of other hormones. In such cases, T replacement may not help.
All the best,