Hi Dave! Good to see you here!
I’m brand new to the guitar too, about three months in with Justin’s course. Finished grade 1 and staying put to solidify chord changes and get comfortable with the basic strumming.
I have the app, and I love it. The lesson videos on it for the courses are the same ones that are on the website, and on the app they currently only go through grade 2. BUT the play along songs on the app are awesome. And like David said, the tempo can be slowed down which is great while learning to speed up chord changes. There are hundreds of great songs on there to play along with.
As far as working on the speed of chord changes…doing the One Minute Changes (OMC) with a metronome has been a game changer for me! I saw it suggested by another member in this community…here is that post, it’s described there…
Happy playing, and enjoy yourself! 