Tell her before you guys spend a lot of money on wedding plans, deposits for rentals, the dress, and other things. It is way better to be honest (and cheaper) compared to getting a divorce later on because you are not happy.
tell her? the best out of these so far is? dude you messed up. LOL. look are you scared? Why the sudden change of heart? I think you think your going to lose on things you may want to do? that scares your thoughts of why now you don't want to get married. better think this over. then make your choice. be honest with her as well as yourself
Just have a long engagement you might change your mind and regrets it and if you don't change your mind she might not want to marry you since you don't seem to know what you want say yes to engagement does not mean your married yet but be honest about the long engagement
Hey this should be a lesson to you .... don't do this dumb crap you seem a little childish over all what you think you found someone better? Poor girl thinks she has her prince charming turns out to be just another d-bag... So you can go ahead and get rid of what you already have or just realize your nervous about promising a lifetime to a probably wonderful girl