I did the same to learn Go and think it’s a very efficient way for beginners.
On my phone I played against app “Go free” (android) which also has many levels of strength, so you can increase difficulty when you need.
I believe that the actual strength of the AI is not really important for beginners: also in live games they have to face many wrong moves made by their opponents. Fighting against a pro-level player is just frustrating. To learn something you have to play against players that are a little stronger than you. Then you’ll improve and you’ll look for even stronger opponents.