okay, since you want to be honest, then you can't use my suggestion.
" you are a distant relative of florence nightengale"..
well it would get their attention.
we had to answer a question like "why do we want to be a nurse". and not say " ever since were were little. etc. .".
i was amazed that some people actually said it was for the the $$$...
have you always looked up to someone that is a nurse, that would help. you are compassionate, understanding, patient, kind, have a knack for science. i think all of those are good qualities.