How old will Reneesme be before she freezes at a certain age?

Oh little Nessiie will be 18 when she stops ageing によって the によって Im a lot like Nessie

18

Well, that depends on what あなた mean. Nahuel 発言しました it would be seven and a half years または so. によって that time she will have aged to about 18.

So depending on what あなた mean によって "how old will she be?" I have to ask if あなた mean literally または looks to be. Literally she will be between 7 1/2 to 8 years old. She will look like she is 18 and have the mentality and maturity of an adult.

17 ..like Nahuel

When she is fully grown up as a Vampire. Which is the age of 18.