Most likely you will have to complete some sort of security background for your clearance.
I'm not going to lie, I would expect to go overseas sometime in your career, but trust me it is a great experience.
My best tour of duty so far was in Korea I learned so much and had a ton of fun. I also worked hard and learned a lot.
Just make sure you ask questions to your recruiters, and check up on things until you are comfortable with the answer they give you. The military is a great life, you get a real sense of belonging and honor while your in. It is hard on you and you family, but there are great support groups.
Now as for MI, if you like to take info and trends and develop various reports and briefs then its for you. Its one of the safer jobs out there, but you can be put into harms ways depending on your assignment. Its your choice, just make sure you have all the info you need.