Depends upon the type of paint on it now. If the bed is painted with an oil enamel, then you should use an oil enamel to repaint it. But black matte is an unusual color.
Just before painting, wipe down with liquid deglosser, after sanding to cut the gloss.
If you want to use a latex flat black paint, you will first have to prime with an oil primer like Zinsser's Cover Stain. LAtex flat black may also be hard to find.
It is going to take several coats of black to get uniform coverage.