You sound like you are a nervous wreck about getting married. It is a big step and unless you can talk about it without wearing a hole in your rugs from pacing, I would dare say you are not ready just yet. Lots of things factor into a decision to marry but biggest issue at hand is are you BOTH ready for marriage. You don't say how old you are, first marriage?, children involved?, any ex's in the wings?
The first time I married I basically married to get out of my parents home. I was 19 at the time and fled the nest without thinking. The marriage was a total disaster as I married for all the wrong reasons.
The second time I married, I married out of pure love and he died a year later.
Having lost twice, I swore I would never marry again because now I was TOTALLY confused as to why people get married in the first place. I had married a jerk, married my true love and soul mate and lost him so what was left? WELL...along comes my present husband and I discovered all the right reasons to marry; yes there are reasons that are right for everyone and yours will become apparent.
The break you are asking for from your girl is a good idea. Gives both of you some space to see how you feel while apart. Good Luck and I hope you find all the right answers.