I think you acted quite appropriately in that situation. Instead of just reacting to them, you reacted, then took over and acted so they had to react to you. You were aware something was wrong, did not over react, took appropriate action to keep a situation from possibly escalating, and then did the right thing by calling police once you were sure you were safe.
I was a bit puzzled about the title of your post though until I read your explanation:
I posted this on another site and there was some confusion about the term "interviewed".
In case anyone doesn't know, here's the best summary I could find in a fast search.
5 Stages of Violent Crime
Using terminology like that, while possibly tacticool for the author, is pretty ridiculous because it can lead to quite a bit of confusion among those whom have no idea of the special use being given to the terms. Yes you explained but I had no idea, not after 30 years of being an LEO no after 14 years as a firearms instructor, that you meant what you did until you explained it. I thought you meant the police interviewed you and wondered why you had made that the subject of your thread when it seemed apparent that the main part of the thread was not about the police interview but was about the guys on the bicycles assessing you with possible criminal intentions.
Imagine that things had turned out differently. As you drove away, in an alarmed state, and somewhat faster than maybe was safe from a car wash, you hit the guy who went to slap your hood. He is severely injured but survives. He testifies as does his friend that they were just hoping to get your attention so you would watch them do tricks on their bikes in the lot. He also says that the only reason he slapped out at your car was because it appeared you were aiming to hit him and coming at him at an usually high rate of speed for the area you were in. You told the cops, upon their arrival, that the guys interviewed you and then that you decided to drive away and then intended to call the cops.
Well, you did drive away, and you were safe, and you called the cops, but you also just ran this guy down. It turns out they have a past history of doing exactly what they testified that they had been doing - showing off on their bikes and they never harmed anyone before. That does not mean though, that you were not justified in having been scared or that you were not justified to take the actions that you did take even if you had wrongly surmised their intent. What maters is what a reasonable person would have thought. Do you think that maybe, you could have used a better way of describing what they had been doing, that alarmed you and made you get out of their quickly, so that you could have better justified your actions other than confusing people by saying you had been interviewed by those two when it fact no interview, by commonly accepted definition of that word, ever took place.
All the best,
GB