It changes a lot and there is a lot of growing up that needs to happen.
You may come to realize that your relationship would work better if you stay friends.
If you are determined to make it work, being a young married couple won't be a problem.
Young couples grow fond of each other with time and become inseparable.
You have a constant support system who helps you get through different phases in life.
You two may grow in different directions and realize that there is nothing left in common.
You work your way through problems in marriage and realize it is a lot different than being in a relationship.