Relationship Advice

I’m currently engaged and am planning to get married when my SO gets back from his deployment later in the year. In December we’ll have been together for 3 years. Lately I’ve been thinking if this is the right decision for me and I’m so conflicted. I love him and he has been head over heels for me since we started dating. I turn 18 in two months and I feel like I’m making a bad decision. My whole family loves him and most of my friendships have been formed because we are dating. We have good and bad days, I feel like if we aren’t fighting we just are saying the same thing over again because we have nothing to talk about. I’m supposed to be the happiest I could be because I’m getting married soon but I feel terrible.

I love him so much and he’s been so good to me. Has anyone else gone through this before or have any advice?