In Maryland and any other states you can only shoot an intruder or someone breaking into your home if the person actually gets into your home.
Also the intruder must also be trying to harm you and you must reasonably feel your life is threatened.
If you can you should leave the house and call 911 and let the police deal with the intruder because it's not worth the risk of yourself getting shot or harmed.
And it's not worth the risk of getting into trouble for shooting someone even though they try to break into your home.
However if you do feel threatened and cannot get out of your home to call 911 or retreat somewhere safer in your home then you might have to shoot the intruder.
But only shoot the intruder as a last resort when you have no other choice.