But think about it though, this generation shinies have been reduced from 1/8192 to roughly half of that, like 1/41XX or something like that. Not to forget fishing, which is extremely easy to do. I have shinies too, but when compared to a legendary, it doesn't have a ton of value, especially as a Poliwag, which you haven't even told us its nature.
Honestly, the best thing to do is to work on your end a bit and put in the effort if you want something. If you want a Mew that badly, you should seriously work for it, instead of asking someone to do the job for you and essentially lowball us. Here you are rejecting low levels and Pokegen created Mews, which is for the most part a wide group of the user base. If you want a decent Mew, you're going to have to lower your standards a bit.