Trayvon Martin was the first to 'Stand Your Ground'?

Trayvon Martin was walking to his Dad's fiance's house when he was accosted after being followed by Zimmerman.

If the above is true, then even if Martin DID in fact strike Zimmerman, were his actions not legal?

Florida Statute 776.012 Use of force in defense of person. — A person is justified in using force, except deadly force, against another when and to the extent that the person reasonably believes that such conduct is necessary to defend himself or herself or another against the other's imminent use of unlawful force. However, a person is justified in the use of deadly force and does not have a duty to retreat if:

(1) He or she reasonably believes that such force is necessary to prevent imminent death or great bodily harm to himself or herself or another or to prevent the imminent commission of a forcible felony;

If Martin was acting legally, what will that do to Martin's claim of self defense? It was after all, Zimmerman who engaged Martin, not the other way around.

Stand your ground, does no equate to close the gap first, THEN stand your ground.