My baby is currently sleeping with my mom

So I came to visit my mom in Mexico I'm from California. My baby is three months & she asked if she could and I said it was fine I want her to enjoy every minute possible with him before I leave. But I noticed he doesn't fall asleep in my arms for bedtime anymore, when he's fussy it's not that easy to calm him down anymore. I feel like I did wrong by letting her sleep with him & basically take care of him during the day