Baby names?

My daughter name is Serenity (6m) & we’ll be bringing another baby into the world in about 5 months & we came to the agreement of Symphony, I loved it at first but now I’m thinking is it too close? I’ve said the name out loud & said her name right after and she doesn’t answer to it but she answers to her name and that was my main concern but any other names that start with S? Do you think it’s too close to eachother? Their dad said after all they’re 11 months apart so basically twins lol