Under Maryland law, a "child" is any person under the age of 18. Read the Law: MD Cts. and Jud. Proc. §3–8A–01

In addition, in some cases the courts will treat a child as an adult:

A child at least 14 years old who has committed a crime that, if committed by an adult, would be punishable by life in prison, will be tried as an adult. Read the Law: MD Cts. and Jud. Pro. Code Ann. §3-8A-03(d)(1).
A child at least 16 years old who is charged with any of the following crimes will be tried in Circuit Court: abduction, kidnapping, second degree murder or attempted second degree murder, manslaughter (except involuntary manslaughter), second degree rape or attempted second degree rape, robbery or attempted robbery, second or third degree sexual offense or attempted second degree sexual offense, violations of gun control regulations, gun violations related to a drug trafficking crime, conspiracy or use of a regulated gun in committing a felony, carjacking or armed carjacking, first degree assault, handgun or machine gun violations. Read the Law: MD Cts. and Jud. Pro. Code Ann. §3-8A-03(d)(4)(i-xvii).
A child will be tried in Circuit Court if s/he has previously been convicted as an adult of a felony and is charged with another felony. Read the Law: MD Cts. and Jud. Pro. Code Ann. §3-8A-03(d)(5).

Your Right to a Lawyer in Juvenile Court

Children who have been charged with committing a delinquent act have the right to a lawyer in juvenile court.  

Your rights:                                                                 

• You have the right to a lawyer at every stage of the juvenile court proceedings.
• Your parents, guardians or custodians can never "waive" (this means to "give up") your right to a lawyer.
• You  can "waive" (give up) your right to a lawyer only if :
  • A petition is filed with the court, and
  • You have spoken to a lawyer and
  • While your lawyer is in the room, you tell the court you want to give up your right to a lawyer and
  • The court decides that (1) you understand what the request means and that (2) you were not forced to make the request.  (The request is voluntary.)

Read the Law: MD Code Cts. & Jud. Pro. § 3-8A-20