With a clean record and absent any factors that would dispose the DA or the judge not to accept you into ARD (it's entirely at their discretion), it's possible.
Typically this gets worked out at or around the time of the preliminary hearing/preliminary arraignment. In fact, they may waive the prelim.
A competent lawyer will definitely help.
The preliminary hearing/preliminary arraignment is where the actual charges are presented and the probable cause for going forward occurs. The cop and witnesses will be there to show that there is reason to continue the prosecution. Typically your lawyer may make some argument about procedure at this point, though it is rare that you would be asked to testify, it's possible. More often than not, this is where the Assistant DA and your attorney will negotiate either ARD entry or some other plea bargain. It's also possible that it will get reduced to a summary offense, in which case they may actually have the trial for the summary offense right in front of this magistrate. If not, the case will be scheduled for trial in common pleas.
The next sound after prelim is that you'll be summonsed for the real arraignment in common pleas. There you will either enter ARD, indicate you wish to plead guilty, or plead not guilty (and ask whether you want a jury trial or not). Then you'll be scheduled for the actual trial.

