Answer: Maybe
Step-by-step explanation:
For someone to have fought in WWI we can assume at youngest they fought at 17 (drafted) meaning they would have to be born in the early 1900's or LATE 1800's. If they were still alive today theyd be well into their hundreds (which isnt unheard of) however the oldest recorded person right now is 114 I think, so while its possible its unlikely.