I would suggest that she plan on getting financially independent quite quickly...get a job, save money for rent and a deposit, check around for roommates, lining up transportation.
I have seen parents refuse to support their children after they reach 18 and/or graduate from high school unless they pioneer. Legally, parents can kick you out at that point and I have seen some do that.
Should they "blackmail" you that way? No. Is pioneering voluntary then? No. But they feel that you are not reaching out spiritually in the right direction and they shouldn't financially support your decision.
So if you don't pioneer, be prepared to financially support your decision.
The other suggestion, to point out elder's children, wives, and elders who are not pioneering is also good.
Blondie