@thumper1 is right.
Unless your DD has identified an outside scholarship that she’s going to apply to and the rules state that FAFSA must be submitted, where would you be submitting FAFSA to? (Again, Stanford doesn’t give merit, so…)
Has your DD found outside merit scholarships to apply to? If so, have her look at the requirements stated for those awards. If nothing is said about FAFSA, then you don’t need to.
As mentioned above, if you do find that FAFSA is needed for a scholarship that your DD has found to apply to, then it can quickly be done and your 2015 info will auto populate into the fields.