What argument will you employ?

As an older man, you know best

Young Matilda seems resistant to her father's advice, even though the Rulebook ought to be making her believe she needs the guidance of older men to make good decisions, but perhaps all she needs is a second opinion from a respected gent (such as yourself).

"Tilly," you begin, maintaining eye contact, so she knows how serious you are, "you should take the promotion. I know you would rather wait, but I'm much more experienced in the ways of the world than you are and I guarantee that accepting the job now will be best for you, your parents, your colleagues and your customers. Whatever reasons you have for delaying don't outweigh the advantages. Go on and contact your firm to tell them you'll take the position."

"Thank-you for your advice, Jack. I really appreciate it and I'm sure you're right, but I'd still feel more comfortable waiting until I feel more comfortable in a management rôle. It won't be long in the greater scheme of things, after all."

"Tilly! I'd've thought a graduate of this esteemed institution would know better than to put her comfort above her duties and responsibilities. I've no doubt you'd prefer to stay safe in your junior position, but you must trust me when I tell you it would be a mistake. Take the job."

The lovely lass nods understandingly, but doesn't give an inch.

"I accept responsibility for my mistakes and treat them as learning experiences. In that way, I hope deferring the position will improve me as a person, despite the downsides. When you're proved right, I'll regret it, obviously, but sometimes we need to experience these things ourselves and no amount of good advice can substitute for practice."

Well, that didn't work.