My husband's only revolving history was as AU on 3 of my store cards, which were only about2-3 years old.
I'd finally convinced him it was past time for him to get a good portfolio of prime cards. He had perfect payment history on 10+ years of car loans, but no revolving credit of his own, and I remember reading another forum member's wise words that the time to get credit is when you don't need it!
His scores were in the 690s, TU was 720+ I think, in April 2008 when he apped for and received:
Amex Gold, Citi Plat, Bank of America and Discover More.
He apped all at once so the inqs would all age together.
Your gf's scores are in the "good" to "excellent" range and I don't think the one CA will be an issue. Often, if something like that is a point of contention with the CCC, you can explain it in a recon.
Good Luck!
FICOS: TU 732(05-16-16) EQ '08 739( 05-16-16) EX 737 (08-17-16)