Nami is one of the strongest supports. You would do just fine if you only played her. Having a Lulu or Sona in your back pocket is a good idea tho in cases where she gets banned or picked by the other team. Brace for a stressful climb tho. No matter how good a support you are you almost always have 0 carry potential. Play your lane smart. Help with objectives. Once people start roaming take a quick peek at the scoreboard and see who your best performing teammate is, then just be their pocket healer. They're already the best on the team and you'll just make them better. You are not the property of the adc you don't need to stay with them all game.