Translation:I am a vegetarian, so I do not eat meat.
Your translation is also correct, and I believe it should be accepted. Please use the Report button next time you get this sentence.
thus is an adverb. In this sentence we need a conjunction and thus is not a conjunction. Although your example is semantically equivalent it lacks a conjunction, which I suspect defeats the purpose of this exercise.
At the risk of appearing pedantic. "I am a vegetarian; thus, I do not eat meat."