How do I kiss my ex-boyfriend that I've never kissed before?

So a few weeks a go my friends hook up guy told my ex-boyfriend that he should go make out with me because he knew that I still really liked him. Well my friend went with the hook up guy and I went with my ex. He talked about stuff that really didn't matter and then he said I'm going to get to it. Justis told me to come up here and make out with you. I smiled and looked away and said yeah I know. Every day since then it feels like every commercial that I see has to deal with love and someone is always getting kissed and people are making out left and right. Like I went to the movies the next day with him and he and I sat at the very top every single person in that theater was a couple and they were making out (except for the one little kid who looked out of place and scared). It made me feel like I should have made out with him. I'm only 14 and the last time we went out was when I was in seventh grade. We went out in sixth grade too but it was nothing to me. I keep thinking about it and I can't forget I don't know what to do... Please someone help. I'm so confused. This summer was supposed to be fun with no regrets and already I have a major one.