Today is Christmas Eve; it is also the third week after starting my new job. I’m nervous and excited, because after New Year I will have to start on lots of work, and handle different partners. I know I will do it perfectly, but I'm just a little nervous, because I haven’t hosted a global meeting before. We don't need "the" before the name of something, in this case, "Christmas Eve". "Commencement date" sounds very technical. I've changed some things to sound a bit more natural. I'm sure you will be ok with you job - that's why they gave you the job! Keep practicing with the writing.