Can you find someone to watch the baby for a couple of hours?
The website is: www.amctheaters.com/programs/sensory-friendly-films
Probably, I think 3weeks is way too early but the one thing I do recommend is if you go on the AMC website they have special screenings for kids with sensory issues like autism. The volume is kept at a lower volume and the lights are kept turned up. You may want to check that out as a better alternative!