So, my personal belief for vegetarianism is I don't buy meat (besides fish). If I am offered meat - I will eat it however.
BUT! Important, all people need B12, but B12 is extremely hard to come by in plant matter other than microorganisms and algae/sea-weed.
So! Either take a b complex pill, or buy some sea-weed once in a while, or eat alot of foods with micro organisms (??)
That is all.