as per the details u have submitted, u are suffering from more of psychological issues than having a real problem.
practically speaking, small penis doesnt affect your fertlity or else your partner satisfaction after a intercourse.
what you should bother about is .... whether you are getting nocturnal erections or not..if u get so...dont bother about aany thing..u are now ready to marriage.
about general belief in masturbation
...? its safe and even better way to get satisfaction than finding a street girl and having intercourse with un known person..so i will tell u one thing ..MASTURBATION IS THE BEST WAY OF RELAXATION. so there is nothing bad about masturbation..and u can marry ur soulmate, with out thinking about your penis size.
hope this will help u lot....