Anna, I know you may be expecting a black-and-white answer, that either kissing is a sin outside marriage or it’s not. I think that the act of kissing, by itself, is not a sin, it really depends on whether the kiss causes a person to lust or not. That makes kissing different than some other intimate acts, some of which (such as, obviously, “going all the way” or whatever the slang is these days), are inherently sinful outside marriage, are some of which are inherently sinful even within marriage, which, considering your age, I won’t go into detail here!
Now, many people believe kissing before marriage would be sinful for them because it would cause them to lust. That doesn’t mean it would be a sin for you personally. In some cultures, any touching, even holding hands, is considered inappropriate before marriage. Many such cultures also think dating by itself is a near occasion of sin, and practice arranged marriage. While some Catholics might think arranged marriage is a good thing, most would prefer to choose their own wife or husband.
I think that for most people, a quick peck on the cheek or lips wouldn’t cause lust, but “French” kissing where you stick your tongue in the other person’s mouth, or kissing and cuddling for a long time (as in many minutes), would cause many people to get “turned on”. Also, boys tend to get turned on a lot easier than girls do, so I think many girls need to be aware that just because something doesn’t cause them to lust doesn’t mean it’s not a problem for the boy.
I hope this helps!
