Sex before marriage as a Catholic?

Obviously, the Catholic church promotes the idea of waiting until marriage for a variety of reasons. However, many of these are outdated, based on old ideas, etc. I haven't had any opportunities yet, but I'm also not totally sold on the idea of waiting until marriage. I'm not crazy religious or anything, I just go to church on most Sundays. Is it possible to have sex before marriage relatively guilt-free and still consider yourself a Catholic?
Sex before marriage as a Catholic?
Post Opinion