Statistics actually show that those who live together before marriage actually have higher rates of divorce than those who do not live together first. If you really feel like you need a trial period to see if you "get sick of each other", then you are not ready to live with this guy, let alone marry him. You do sound more mature than most 18-year-olds, but yes, you guys are young. That doesn't mean your marriage wouldn't work, I got married at 21 and it's been 13 years and two kids and we're still happy. Getting married young doesn't mean it won't work, it's just another thing that makes it a bit harder. I think if you were to get married in the next couple of years, you'd be putting too much stress on you guys as a couple. The first two years of marriage are SO HARD! During that time, you'd still be going to school and/or trying to get into a career, which means even more stress on the marriage. On top of that, you guys are young...and don't exactly always make the most mature decisions (I know I didn't - even at 21), which adds more stress. With the cost of school, you'd add money problems on top of that. You might as well go ahead and file for divorce at the same time you apply for marriage, LOL. If you guys really love each other and are truly meant to be together for life, they why not wait?