If you have already received a offer for your dream job I wouldnt pass that up. If you like the field that the first degree has put you in, then you can slowly get that second degree on the side while working the dream job. If you didnt like what you were doing right now and the first degree was in something you didnt like,then I could see why you would want to hurry up and finish the second one. Sounds like you are in a pretty good position right now. Good Luck.