Thanks for choosing health care magic for posting your query.
Please try to understand that masturbation
is a safe way of fulfilling your sexual desires. By this way, neither you can make any one pregnant, nor can you acquire any Sexually transmitted infection. Its only abnormal, if it is done in excess with compromise to our daily routine activities. If that is so, then you surely need to discuss the issue with a psychiatrist
Coming to your second concern, a penile length of 12 cm and 11cm girth is more than sufficient to have sex and satisfy your girl. So please dont be anxious about it. And pertaining to the time of sexual activity, your 30 sec of masturbation cannot judge how long will it take in the actual sexual encounter.
Dont be so anxious from now it self. Let the right time come and you will understand that your concerns are not warranted. Even if in the actual sexual encounter you have a premature ejaculation
, there are good drugs available to cure that too.
Hope I am able to solve your concerns.
Wish you good health.