Here, you two couldn't be a mixed USTA league team unless she wants to self-rate at 4.0 (which would nix her for the 3.5 team).
Methinks she might not be ready for 4.0 on a 9.0 mixed team unless her volleys are spectacular. If not, they'll crack everything to her at net and it will be a long hard slog.
Maybe she could play 3.5 this spring and then if she dominates you'll have a better idea?
-- Random Error Generator, Version 4.0
-- Master Moonballer