<human>: Can you give me a shortened version of the text?

Says she wants to wait until we're engaged and moved in together before sleeping over. 

She's from a Latin American background so not as liberal as most north American people I guess. She still lives at home with her mom (62F) who is strongly opposed to her sleeping over because "it would be inappropriate" and she would be uncomfortable with the idea of it. Other than that, her mother and I get along really well and I'm the first and only BF of her daughter she's ever liked / approved of...
Her mother knows that we plan on getting engaged in the next year, she knows we've travelled together and slept together before, she knows we're sexually active, she definitely enjoys how happy I make her daughter and how well I treat her, etc 

I've asked my GF to help me understand why it's such a big deal and it basically boils down her wanting to "do things the right way" and "being able to say we were able to wait"... 

To me, that kind of rhetoric makes total sense if we were younger and/or not yet sexually active but really doesn't make sense when talking about adults with careers and lives well under way... Plus, we've already spent nights together in hotel rooms when travelling! 

All in all, I'm baffled. Maybe I'm being insensitive and need some perspective? Any thoughts on this? As much as I would enjoy having my GF sleep over, I'm totally willing to forgo this until we move in together BUT I just want to understand! My issue with this is that they're so stubborn about something that doesn't hold much logic to it.
<bot>: my (25M) GF (25F) refuses to sleep over because her mother doesn't approve, even though we've been sexually active for months and have spent nights sleeping together in hotels when travelling.