Yes, language switching feature like that would be so much help. When I was in middle school I started watching movies (in English) with English subtitles, then without subtitles.
Didn't work out well, I couldn't understand like, half the movies I've watched lol. So did with games. But it was a great practice. And now I can understand... pretty much everything without subtitles. Now my English is still not perfect, but definitely better than I used to (Imagine how atrocious I was).

I wish I could watch anime without subtitles. I think I've learnt some simple Japanese sentences like you said, something like "I am... .", which is something that the 15 y.o. you understand and I recently learnt years later. This is some very good tips from an experienced person, so thank you!