That is quite acceptable but if you tried so hard you could try a bit more to get max defense IVs, one stat point may make a difference between a win and a loss. Not all the time. It it's OK for you to lose a match that could have been won with perfect Def IVs, then sure, keep this mew. (The circumstances are rare, but it happens).
U could use AR/powersaves to get a perfect mew with 31/x/31/31/31/31. Preferably x being 0 if you don't plan on running knock off, to make sure you take less damage from confusion/foul play.