What does it mean when the judge says he is with holding adjudication?

Deferred adjudication is available in some jurisdictions for first time offenders for certain offenses. It often involves probation, treatment programs, and/or some type of community supervision. If all the conditions of probation are met for the allotted time handed down by the court, the offender can avoid a formal sentence, and in some jurisdictions, no permanent record of the crime will be made. Typically, at the end of the probationary period the charge will be dismissed and no record of conviction will result. Deferred adjudication may be available to eligible defendants upon recommendation by the prosecutor or at the discretion of the court. 

Note, DO NOT violate the terms of your probation or you will have to serve your sentence.  Also, some jurisdictions will not show a conviction on your record  but they still may show an arrest.  You may want to ask the court or an attorney licensed in Florida about this.  To get the arrest record cleared you would have to have it "expunged".

In simple words, the judge is going to wait, before he actually finds you guilty.

This is a good thing, for you.  You are a first offender, and the judge is giving you the chance to do your probation, without getting into any more trouble.  If you can do that -- do everything you are told to do (and not do everything you are told not to do!) as part of your probation, not get arrested, the charges will be dropped, and you will not have a conviction on your record.

On the other hand, if you get into more trouble, before the charges are dropped, you will have the original conviction, plus whatever else you get for any new arrest, and you'll be a multiple offender, with a good chance of going to jail.

Quite literally, this is a once-in-a-lifetime opportunity.  Don't blow it!