Nervous about growing up & moving on?

I haven’t had the easiest life and always felt pretty stuck in the same place. I had an amazing man come into my life & made me feel alive. I am planning to marry him soon but feel a little nervous. I am so used to my current state and change seems scary. To top it off I am very close with my parents and I’m always there for them (one is sick). I just get a little scared if something were to happen & I think I’d never forgive myself for not being there for them. However, they tell me otherwise and say it’s time to live my life. I just hate the idea of being so far away even though it’s my dream to live where we will be going. I sometimes second guess myself & question my relationship. I get a little scared of coming out of my comfort zone. I’ve never really dated much - nothing serious at least. I’m just not sure what to expect? I have a lot going on in my life right now and I’m seriously stressed out and have anxiety from time to time. I sometimes don’t even know how I really feel and my feelings always fluctuate. Is it normal to just not know what you want & afraid of making the wrong choice? I’m in my early 20s & I have a long road ahead. It would just help knowing I’m not alone in this.