About 2 years maybe a little less
Ok, great. The reason I ask is that siblings with smaller age gaps usually have more similar names [examples: my little sister and I (three years) have the same first initial and middle names that start with consonants, my nephew and niece (also three years) have the initials RMD and MRD, but both go by the "R" name).
Following that logic, Leightyn Alexis would fit well. I can also offer up Londyn Sofia, Genesis Layne, and Laken Everleigh.
Or, for something a little edgy but still befitting a classy Southern belle, try Raleigh Knox, Hollis Wynn, Waverley Anne, or Delaney Roe.
I hope these help in some way!