I am so sorry that I only write now, I didn't feel so great when I made that post almost a month ago. Learning a language on your own is really hard and requiers a lot of disciplin. I have a lot of respect that you learn Japanese. When I learned English I actually did what you were thinking about and threw myself into the deep and went to Australia in 2015 for 4 months to learn English with the money I saved up. I could only make a few sentences and it was my very first time taking a flight alone, actually it was my first time to travel alone too. Thinking about it back then I was even afraid of ordering food from a waiter in my own language at home because of my stutter. So forcing myself in a situation from which I can't escape on the other end of the world helped me quite a bit to learn English and face what I fear. I hope I didn't come across as weird, oh and btw. I made a few Japanese friends in Australia and it is a really interesting culture to learn about. I think it is great that you have contact with native speakers in your church.