Speaking from experience never move in with family and a spouse. Never ends well. Save and get your own. You'll be better off trust me and everyone else saying the same thing.

I would say no to moving into her house. Do y’all live together now? Knowing from experience I would enjoy your space. If y’all just started being a real couple this last past month then y’all need to work on building a bond and a solid foundation because living together is a struggle of its own. It won’t be pretty everyday so if the relationship is just newly going good I wouldn’t put the unnecessary stress onto it.

I wouldn't be moving

I would stay where your at unless moving in with her is beneficial like you guys are able to save money if that’s not the case I would stay put . Talking from past experiences I would only move in with her to save money and able to move out and be on our own . I hate living with other people you don’t have your own kitchen or living room it sucks cause for me I love my own space & all . I’m currently living with my SIL & there’s days that I regret making this decision but it’s all because we don’t make it alone and living with her we have a few money left at least . So yeah ...

I don’t think I would want to move my son into my sister-in-law’s garage. I think you should save your money so you can have your own space and feel good about it