I had the name Eleanor Caroline picked out a long time before I even conceived dd2. Dd1 even referred to her hypothetical sister as Eleanor. While pregnant and just after she was born I felt strongly she should be Isabella. I knew that would totally throw dd1 for a loop, though, plus I was concerned about the name's popularity. That wouldn't have stopped me, though, if that was the only issue. I think Sophia and Isabella go very well together. I still feel sort of wistful about not naming her Isabella. I only know one Isabel in real life, but I've seen *many* here on the boards! (see above :LOL ) Caroline was in honor of my mom, but she didn't like it, so after she went thru the hellish nightmare that was my birth experience with me, I told her she could pick out the baby's middle name. She said she felt like the baby wanted to be Elizabeth. She didn't know about the Isabella/Elizabeth connection, but I did, so I knew right away that that was it. Eleanor Elizabeth. She winds up being called Ellie, Ellie Bellie, Ellie Belle, Bellie, and Belle.
I think if you love it, it feels right to you, and suits your dd you should go with it!