How do I tell my parents that I want to start a YouTube channel?

[Carolina]

I've already set up the account, added a description, subscribed to some people, added channel art, everything put upload a video. I don't want to do so until I ask my parents it it's alright for me to. I'm planning on purchasing a laptop and nice HD camera, but they said they could help out in buying the laptop. How do I tell my parents that I want to start a YouTube channel? I never really ask anything like this, and I think it would be kind of weird... I'm probably over reacting, though. What should I say to them to make them go with it? I plan on doing vlogs, tutorials, parodies, sketches, challenges, etc. I do have a twitter, tumblr, instagram, and vine, but I haven't told them about those. I'm pretty sure they know about the twitter and instagram, though. Please help me! How do I tell them I want to start making YouTube videos in a way they'll agree with?!

Also my channel is: http://www.youtube.com/channel/UCE_D88wNlmvbzWapKMPE6sQ
Please check it out (although I have yet to post anything, obviously! I will soon!)