Never lie! (or “stretch” the truth about what you’ve done or not done). Everybody has to start somewhere. If you’re honest, and clearly express your enthusiasm and eagerness to learn, then I don’t see you having any difficulties.
Consider avenues/facilities where your expertise will be valued (it may not be paid yet, but you never know:):
-local rec centres (offer to teach (or co-teach) a class)
-local media (position yourself as a trained health/fitness professional, ’cause you are!)
-clubs or gyms where you can walk the floor and be available to answer member questions
-heck, apply for an actual job! you never know what opportunities are out there and who you might meet (it may turn out to be your mentor!).