How long did it take your child to learn how to use an AAC device?

Hello, my daughter is 3 and currently trialing an AAC device at speech therapy. I believe the app they use is called touch chat?

Her pre-k teacher and school ST also use the same app in class and it’s been about 4 months since she started. She is still showing little to no interest in using an AAC device when guided to do so.

We don’t really use any type of tablet at home for her and I was wondering if I should introduce one at home to encourage her to learn how to use touch chat. She’s a gestalt learner and uses a few words / phrases functionally, with some sign language (on her terms) as well.