technically the answer would be YES anyone could start booking travel (even without taking any courses) but like Luv2Travel points out, they'd need to be affiliated with an established agency to do so.
so she might be new to booking and setting herself up as an at home independent contractor of a host agency.
and like Luv2Travel also pointed out, check affiliations and credentials. Does the individual agent and/or host agency belong to CLIA, ARC, IATA, etc. Do they belong to OSSN or NACTA? How long has the AGENCY been in business (more important that how long the agent has been booking travel). What kind of E&O insurance do they have, if your state requires sellers of travel to register with the state have they done so (Florida, California and a few other states require this). Even if they are not in your state, if your state has SOT laws they have to register with the state before they can sell travel to any residents in that state.