Stacy, you seem to have a reasonable head on your shoulders on this matter. I applaude you for that.
Here are my thoughts:
For most of us (cult issues aside), do the vast amount of maturing in our twenties. You are not yet twenty one. The outlook you have now, will most likely not be the same outlook when you are thirty.
I believe that before marriage, you should have some life experience. That means graduating from college, getting a job, supporting your self, paying your own bills. Doing mundane everyday tasks. Not for a few months, but for a few years, on your own. No living together. You depending on you.
Studies have shown that marriages that have the best chance for success are the ones that are delayed after the age of 28. That doesn't mean you can't have a happy marriage. It's doesn't mean that others haven't done it and been successful. It just means that the odds are against you.
I was also so sure that kids were not in my future at your age. Now, I have two. I've seen it go both ways. My best friend is childless by choice and been married many years (She's 40). However, I also have seen divorces because after a few years of marriage, one partner had changed their mind regarding kids once they hit their 30's (it was the husband). So, never say never.
So, I guess my vote is not to rush it.
Best wishes.