Solution

159921

First name
Erica Sarah and Annie
School
Wenona
Country
Age
10

These are the answers we got for Roman Numerals:
III = 3
IV = 4
XVIII = 18
XIX = 19
MCMLXXVI = 1976
MMXXIII = 2023
MCMLXII = 1962

55 = LV
86 = LXXXVI
2592 = MMDXCII
913 = CMXIII
1984 = MCMLXXXIV