posted mixes don't really count, man. i've just been doing this longer than you. of all my mixes, i think one's made it through the panel, maybe? the rest have been DPs, and all of them either had major issues that got overlooked, or i had help on them. do a search for mephisto or prophetik in the judges decisions forum, and tell me that i haven't had trouble getting posted when i don't get DP'd now, some of them got rejected for ridiculous reasons, sure (i was told one was too far from the source when it was the exact same notes as the original, no changes, slowed down a bit), but that doesn't mean that those songs didn't all have a bunch of production or mastering issues as well.
the key is to always keep getting better, no matter what. you don't want to look back in a few months and think, "you know, i don't think i can top that". you always want to be able to look back and say, "i wonder if i change this, how much better it'll sound".