You don't need any musical background to begin. Beginner guitar lessons start with posture, a clean single note and two chords you can move between. Most learners can play a simple song recognisably within a few weeks of regular practice, though chord changes stay slow for longer than people expect — that lag is part of learning, not a warning sign.
You do need a playable guitar. If you haven't bought one, ask before you spend; we'd rather point you toward a sensible used instrument than have you buy something with a warped neck that never sits in tune. Tell us your budget and whether you want acoustic or electric, and we'll narrow it down from there.
Age isn't the barrier people assume either. We teach teenagers and adults, and the early lessons look similar for both. What changes is the music you bring in and how much time you can put between sessions.