OK, don't take this the wrong way, but you sound pretty naive and immature judging from your reponses to comments in this thread, and your original post as well. I KNOW you don't think you are, but trust me, you are. Even if that weren't the case, what you're asking about would still be a bad idea. Given your naivete/immaturity, this is an extremely bad idea. I'm coming from a sympathetic place here. Every girl at some point wants to have some throw-caution-to-the-wind type of relationship. It seems romantic and spontaneous, and even more exciting because of the "Forbidden" nature of office relationships. I GET it.

Don't do it. Give yourself a few years to still be young and be with people at your stage of life. I dated a guy a bit older than me, and i thought it was just a number. It's not. 3 years later it feels like we dated a lifetime ago, I'm still not as old as he was at the time we were dating, and I CANNOT believe I ever dismissed the age gap or differences in maturity/experience. Oh, and I worked with him too, but we were the same "level". People talked, it was annoying. Given the chance, I would not do it again. There will be more guys. Better guys. That don't work at your firm and have the power to fuck with your job.

You have two choices. Don't date this guy, kick butt at your internship, mature a little as a profession and as a woman. You could have a full time offer on the table at a big 4 firm and set yourself up with a wonderful start and great foundation for your career.

Or you could date this guy, deal with office gossip, have people second guess your position because you're bedding a higher up, end the relationship badly (this is the ONLY outcome I GUARANTEE it). No full time offer. Your career isn't over but it's not off to as good a start. Will it have been worth it? Only time will tell.