<human>: I'm (26M) deeply in love with my new girlfriend (25F), but i'm afraid I'm about to break her heart by telling her the truth.

Our mutual friend Ben set us up. So, on our first date she started telling me how she respects my job so much and she was so excited to meet someone that's working to improve and help the wildlife on our only habitable planet, rather than destroy it with the over-consumption of natural resources. I asked her how she knew what I did for a living, and she told me that she looked me up on facebook where she saw my save the whales' t-shirt in my profile pic. Apparently, she then asked Ben about the t-shirt and what I did and he literally told her that I was a marine biologist!!! But this is not really the case, because instead I work for a large company in the oil and gas sector. I don't know exactly why I let it happen, but I did. I wanted to tell her, but I was already nervous and I have trouble communicating sometimes. I really wanted her to like me I guess. 

My biggest fear is that this could actually be a deal breaker for her. She's vegan, drives a prius, and she used to be in an ecology club in college. She also has some minor trust issues from her ex-boyfriend. So this could really hurt her when she finally finds out.

Lately, she has been talking a lot about the keystone pipeline and the environmental impact it will have, which is making me really reevaluate not having told her before, but it's also making me nervous about how she will feel about me when she finds out what I really do and i'm scared she will think i'm some kind of monster.

I've never felt this way about anyone before and I have no idea what to say to her.  The longer this goes on, the harder it will be to tell her, but the sooner I tell her, the sooner I may find myself without her, and I can't see myself losing all that we have together. How should I tell her?

Can you condense the text into a few key points?
<bot>: I'm in love with my girlfriend who thinks im a marine biologist and I don't know how to tell her the truth