Best thing to do is talk with them about doing that and show them what you're going to do. If you're up front with them about it then I think they'll understand as long as you keep it clean. Give it a shot and see what they say. Can't hurt to ask.
I want to start a YouTube channel, but I'm not sure my parents will approve, and I'm kinda scared of the hate I might get. What should I do?
Couldn't you fix your You-tube channel to accept comments from friends only or friends only from Google + account? I do believe this setting can be set ..This way if anyone wants to comment on your you-tube channel they would need to add you as a friend this lets you keep everyone accountable for .
I do Youtube myself and my parents don't know. Personal experience from me - would be do the videos either before or after your parents are asleep. As for hate comments, either mark them as spam or fight back but I doubt you'd get them so early on after starting.