Well, I have to say that the hair of your gf, judging from the video you shared, looks A M A Z I N G !!! Sure, it's not Rapunzel Length, but you don't know what the future holds. Who is to say she'll never grow it longer?!

But, since you asked for advice, if I were you, I wouldn't focus too much on the length. Just make sure to take good care of her and her hair. You can also offer her to do regular trims for her, that way you can help her maintain the beautiful quality and even make the length of her hair a topic of discussion.

Wishing you all the best in living your dream!