I understand and appreciate every opinion on the thread, that is what it is for, to disucss the topic.
My Story:
Met my then "bf" at 15 years old, at the time he was 17 yrs old. We did the typical high school thing, went to prom, day trips to the beach, first jobs, and so much more.
In 2005, my then "bf" graduated from high school and went to Albright College. We still stayed together during this time, even with my 2 years of high school left.
-In 2007, I graduated from high school and also attended Albright College. This was my first choice college way before I met my "bf", my parents had been visiting the college at an early age.
-In 2009, my then "bf" graduated from Albright College and accepted a degree in Accounting.
-In 2010, I graduated with an honors degree early in Accounting and Business and accepted a Staff Accountant position.
-Before graduation, at age 21 for me and age 23 for my the "bf" we got engaged.
-January 2011 we purchased a home.
-Our wedding date is set for May 5, 2012. We will be engaged for 2 years.
So do I agree with getting married young, sure if that works for you. For me, it didn't matter either way. We were together through everything and every experience life wanted to throw our way during those years. Married or not married, we still were a couple.
Personally at the age of 18, I would have been mature enough to get married. However, it just was not the right time for us in our life.
Everyone has their opinions to the story of course!
Now how I really feel - Haha there is no way I could afford a wedding at age 18! I can barely afford this wedding for age 22!! 

Great thread OP!