wow ilthl! what a zchus to be such a shaliach of Hashem!!!!!!! that’s amazing!!!!!!!!! i recently tried to redd a few shidduchim, too. i must admit, it takes tons of strength to call someone with an idea, and of course you may be way off the mark! but tell your friends (or whoever you were talking to) that some of the biggest shadchanim can also be way off the mark! tell them to remember that shidduchim come from Hashem, not the shadchanim. if Hashem doesn’t want a shidduch to go thru that a shadchan redd, then He will make that not work out, too, sometimes making something way off the mark!
but think of it this way: if it would work, wouldn’t that feel so amazing and rewarding? you were the shaliach in helping this couple to build a bayis ne’eman! that is such a big zechus! biggest thing to remember: (not to take anything away from the amazing work of shadchanim) shadchanim are people too! they had to start somewhere, just like you! and they are not always right either!
now, as far as not knowing what to do once you have an idea, either see if you know someone who knows both sides, and if they would feel comfortable redding it, or call a shadchan and tell him/her of your idea. or tell a parent/teacher whom you are close to. hatzlacha in this amazing avoda!!!!!!!!