Preparing for your first mountain hike does not require being an athlete, but it does call for gradual conditioning that lets you enjoy the route rather than endure it.
Start by walking 30 minutes a day and gradually increase the distance. Add stairs or slopes twice a week to get your legs used to climbs. Consistency matters more than intensity.
Build endurance with long walks on weekends, too, and don't forget to stretch before and after. With three or four weeks of preparation you'll be ready for a DO-RE or MI-FA-SOL route.
And remember: at Sal Si Puedes we classify every route with musical notes so you can pick the one that suits your current pace.