No, Jesus was not a vegetarian. He partook of the Passover Meal which was lamb.
- Exodus 12:3,6-7, 11, “Speak to all the congregation of Israel, saying, ‘On the tenth of this month they are each one to take a lamb for themselves, according to their fathers’ households, a lamb for each household”..." 6‘ And you shall keep it until the fourteenth day of the same month, then the whole assembly of the congregation of Israel is to kill it at twilight. 7 ‘Moreover, they shall take some of the blood and put it on the two doorposts and on the lintel of the houses in which they eat it... 11 ‘Now you shall eat it in this manner: with your loins girded, your sandals on your feet, and your staff in your hand; and you shall eat it in haste—it is the LORD’S Passover.”
- Mark 14:13-14, And He *sent two of His disciples, and *said to them, “Go into the city, and a man will meet you carrying a pitcher of water; follow him; 14 and wherever he enters, say to the owner of the house, ‘The Teacher says, “Where is My guest room in which I may eat the Passover with My disciples?”’
It is not wrong to be a vegetarian. Each person is free to make that choice for himself, (Rom. 14:1-12).