He said He wouldn’t drink again of the fruit of the vine until it was fulfilled in the kingdom.
He drank and recognized it as wine.
He still would have sinned if He demanded that the disciples drink it intending it to be blood.
God is the one who instituted the prohibition against drinking blood and it was reiterated at the Council of Jerusalem.
God never changed His mind on the issue.
Matthew (the only "eyewitness" here) says Jesus "took the cup and gave it to them saying 'Drink from it, all of you.'" {Mt. 26:27]
But then he said he would not drink of "this fruit of the vine from now on until [6:29] he sees them in the heaven.
From now on until...since he didn;t drink any but rather blessed it and gave to to all of them, he didn't drink of it.
However, it is strange (to me at least) that he first calls it the "blood" of the [new] covenant and then the a mere "fruit of the vine."
What is being instituted here is either some miraculous sacrament (mystery) or an empty and meaningless ritual. Every time people pray to God they remember Jesus, so why go through special ritualistic remembrance of taking of the "blood of the covennant" and eating of the "body" (both of which are portrayed as life-giving) unless it is to impart some qualities on those receiving them? And why would Paul warn that one should not receive them "unworthily" if they are a mere "remembrance" or just plain bread and "fruit of the vine"?
Incidentally, according to-the Synoptic Gospels, the order of giving thanks, first for the bread and then for the wine, is the exact opposite of what the early Christians practiced (see Didache), as well as of the Jewish custom!
I am not sure what prompted this reversal, but it seems strange that an observant Jew would institute them.