You seem to be open to some harsh truth. I won't be too hard on ya
Especially because I appreciate the effort and what you're doing.
For a first time effort, it was not bad. Definitely work on the tips already given, and as you go on, I am sure your nervousness will be gone in time.
That said, production wise, it was completely jarring. First of all, you seem to be filming from a phone, yes? That is fine, but you have to absolutely shoot in landscape mode. If you need to show more of your body and such, just move back.
Secondly, again, because of the nerves, you move in and out a lot. It is very distracting. Especially when teaching. You should be more stern and assertive when teaching, imo.
Other than that, looking good. And looking forward to seeing more
Edit* Also, where is Kaori?