Masturbation is something some people do every day all of their lives whether they are married or not married.
NOTHING bad can happen to you because you masturbate - not now, not after you are married.
Some people masturbate after they get married or they have a boyfriend or girlfriend. People might do that because,
1. They like to masturbate;
2. They like to have sex more often than their partner does; 3. They like to have sex longer than their partner does, or
4. They like to show their partner what they enjoy to help them to be able to do it the same way.
Don't worry about masturbation, I promise it is OK.