Always good to have a riding partner, and good to hear you could both compromis and fit well together...
She'll be very string having always riden on such a heavy bike... now, if speed is someh\thing she desires, it shouldn't take much to convince her she needs another bike (please note, ANOTHER bike - NOT trade-in her existing bike) and she will be zipping along more quickly like you can!
Glad you had a great day