ROTC infantry MOS???

After finishing ROTC I want to go into Infantry or MP. After finishing ROTC, I heard that getting into infantry is hard because it is the most popular MOS, and only the top ROTC cadets get the MOS that they want. I just don't want to get stuck as a officer in a logistics warehouse or a desk job. Does anybody know hoe hard it is to get into infantry or MP after ROTC?