Go to
www.firehouse.com , pay the fee, I think it's like three months for 7 bucks or something, and then access their job search engine. They have categories for all sorts of positions. You can search for EMT/paramedic EMS only, FF/EMT or medic, or FF only. You can search state by state.
I used it for Fairfax County and also Charleston County EMS.
Just have your parents put the fee on their credit card, and then you can search to your heart's content. The job posting will generally tell you the age requirement, any necessary certs, job description, salary range, benefits, and typically has a link to that organization's website.
Anyway, to answer the OP's question, most if not all of the major depts in the MD/DC/Northern VA region will allow you to test for the position with only a GED, clean driver's license, 18-19 Y/O, no drug use for 1 or 2 years, no significant criminal Hx.
Some depts to check out would be D.C. Anne Arundel Co, Prince Georges Co, Howard Co, Montgomery Co, Annapolis, Baltimore, Fairfax County, Prince William County, Loudon County, and Stafford County. You can also check out Phoenix, or various depts in Cali.