You aren't going to listen to any advice that is attempting to direct you away from this decision, so it really is a waste of time.

You are soliciting an answer to a question where many of the members have had more than one marriage and maybe made the initial decision very early in life. Yet, you aren't even interested in listening to what they have to say. (where's Shiner when you need him?)

Get your personal life together before making such a big move. Another person isn't going to make the "last 4 years of teenager-ness. - slags, cheating, fights, exams, Fs, ungradeds, fails and flunks."

Make a commitment to and for yourself, before making a commitment to someone else.