Yeah, it's probably a change from how you've been learning up until now, but having to do your lessons all in Japanese will pay HUGE dividends long-term. I agree with Zgarbas: my experience is that it's hard to find tutors who are fluent in both languages, but it's really easy to find a ton of good tutors who are fluent in Japanese only. (And there are a lot of reasons why some tutors with perfectly acceptable English will not mention that they can speak it, but that's another thread.)
One nice thing about learning in Japanese: no translation filters to worry about clouding up the meaning of things. Not saying that 日本語文型辞典 is bad, because I just raved about it on the last page, but translation means another person interprets it, then figures out a way to say it in English, and in the process, bits of meaning invariably get lost. So if you really want to zero in on stuff, then translating is always going to be a sloppy tool. That's been my experience with it, anyway. (Look at chapter 1 in KZM 文法 N1: you could translate almost all of them as, "As soon as," but that doesn't really convey the proper shades of meaning, right?)
If you're not confident about your ability to hold down a conversation in Japanese, start with small group lessons in conversational Japanese at JOI, and maybe some grammar classes a level or two lower than you need, just to get used to it. The group lessons are pretty inexpensive, and they're "safe" in that there are usually a few other people there who have to speak as well. (And really, nobody cares if you make a ton of mistakes early on. That's what the class is for-- to make a ton of mistakes and learn how to carry on a proper conversation.)
One nice thing about learning in Japanese: no translation filters to worry about clouding up the meaning of things. Not saying that 日本語文型辞典 is bad, because I just raved about it on the last page, but translation means another person interprets it, then figures out a way to say it in English, and in the process, bits of meaning invariably get lost. So if you really want to zero in on stuff, then translating is always going to be a sloppy tool. That's been my experience with it, anyway. (Look at chapter 1 in KZM 文法 N1: you could translate almost all of them as, "As soon as," but that doesn't really convey the proper shades of meaning, right?)
If you're not confident about your ability to hold down a conversation in Japanese, start with small group lessons in conversational Japanese at JOI, and maybe some grammar classes a level or two lower than you need, just to get used to it. The group lessons are pretty inexpensive, and they're "safe" in that there are usually a few other people there who have to speak as well. (And really, nobody cares if you make a ton of mistakes early on. That's what the class is for-- to make a ton of mistakes and learn how to carry on a proper conversation.)