Hi.
Firsts are often given such a huge weight. To say that first kisses aren't overly romanticized by people would be a total lie -- everyone does make a big deal about them. But luckily your first kiss won't act as any sort of definition for what happens later in your life.
Having your first kiss not be entirely voluntary can be completely traumatic, and I understand why you would be turned off to any future kissing experiences. What your ex-boyfriend (and the people you were hanging out with at the time) did was absolutely wrong -- from the abruptness of the kiss to the pressure you were put under to the fact that he turned it into a huge public spectacle. I'm sorry that you had to wind up feeling bad about it something that was pretty much out of your control. Did you later tell this guy how upset you were?
It may be that you are doing the right thing by staying away from dating until you feel right about it, because even though most people out there probably won't be so inconsiderate of you and of your privacy it might be hard to separate the memories of your first kiss from later ones. But kisses are very unique. And it is important to not let this extremely uncomfortable situation get in your way of having a new completely different experience.
I am pretty sure that a number of people have had terrible first kisses. At least I am sure I did.