I don't think it's too similar to have your child's initial matching yours. Most won't note it (unless you have more and call them Elise, Electra, Ebigail and Esther).
Emma is extremely popular. Not only is it a top hundred name at the moment, but it been in the top hundred since 1974, spent 1974-1994 in the top ten and since then has never been ranked lower than 60th. While a name ranked 60th for her year of birth might not be alarming and she probably won't share every classroom or dance class with another Emma, the cumulative effect of these decades of Emmas means that she will likely always work with another Emma or have another Emma in her circle of friends when she grows out of being kept in age groups. I know you've only asked about popularity at the moment, but I think popularity outside of your year of birth is just as important. I know people who were the only one of their name in the classroom, but then as adults found it frustrating to be one of five in the office with their name.
Louisa is by far the nicest of the three names in my opinion. Emma's years of popularity just make it dull for me, and Lucy also feels a bit dull and wet. I do like Lucia though.
