Ive never been inpatient for my eating disorder, almost did but thankfuly i didnt end up there. First off you will prob want to see your dr and get your vitamin levels checked and everything to see how healthy or not healthy you are, i beleive they do check you over to let you be inpatient, if your weight is dangerously low or your at risk for health problems. Sometimes if you arent doing that bad with the eating disorder they may recommend an outpatient program or therapy sessions, it alll depends on your situation.
Im happy that you told your mom about it, its hard but you feel so much better once they know. SOmetimes our parents wont reach out until you reach out for help yoursel fbecause it does nogood to you or anyone if your not ready for recovery, you cant force someone to recover they have to be ready themselves. I wish you the best in your recovery and we are all her for you if you ever need to talk or find yourself struggling.