Bring the thing only you can bring

A seventeen-year-old cannot realistically model total cost of attendance, currency exposure, or what a family can afford without strain. You can. That is your genuine contribution and it is a large one.

Set the financial boundary clearly and early — 'we can support up to this, here is what that means' — and then let the field be theirs. Constraints given early are useful; constraints revealed late feel like betrayal.