Kudos to you for supporting your child in this endeavor, as many say that it is easier to learn a language when one is young.

Although there were fewer resources back in the day, we had a family member intent on learning various languages.

Related article:
Why It's So Hard to Learn Another Language After Childhood
by Jamie Ducharme
May 2, 2018
TIME

This recent thread may also be of interest:
Great foreign language curriculum